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|---|---|---|---|---|
1001.1240 | Multicritical Points and Crossover Mediating the Strong Violation of Universality: Wang-Landau Determinations in the Random-Bond $d=2$ Blume-Capel model | The effects of bond randomness on the phase diagram and critical behavior of the square lattice ferromagnetic Blume-Capel model are discussed. The system is studied in both the pure and disordered versions by the same efficient two-stage Wang-Landau method for many values of the crystal field, restricted here in the second-order phase transition regime of the pure model. For the random-bond version several disorder strengths are considered. We present phase diagram points of both pure and random versions and for a particular disorder strength we locate the emergence of the enhancement of ferromagnetic order observed in an earlier study in the ex-first-order regime. The critical properties of the pure model are contrasted and compared to those of the random model. Accepting, for the weak random version, the assumption of the double logarithmic scenario for the specific heat we attempt to estimate the range of universality between the pure and random-bond models. The behavior of the strong disorder regime is also discussed and a rather complex and yet not fully understood behavior is observed. It is pointed out that this complexity is related to the ground-state structure of the random-bond version. | [
"Physics Archive->cond-mat->cond-mat.dis-nn",
"Physics Archive->cond-mat->cond-mat.stat-mech"
]
| 2010-01-08T11:02:46Z |
2203.11906 | X-ray cluster cosmology | Formation of dark matter halos is sensitive to the expansion rate of the Universe and to the growth of structures under gravitational collapse. Virialization of halos heats the gaseous intra-cluster medium to high temperatures, leading to copious emission of photons at X-ray wavelengths. We summarize the progress of X-ray surveys in determining cosmology using galaxy clusters. We review recent cosmological results based on cluster volume abundance, clustering, standard candles, extreme object statistics, and present relevant theoretical considerations. We discuss clusters as gravitation theory probes and present an outlook on future developments. | [
"Physics Archive->astro-ph->astro-ph.CO",
"Physics Archive->astro-ph->astro-ph.HE"
]
| 2022-03-22T17:18:33Z |
0912.1329 | Energy Efficient Scheduling via Partial Shutdown | Motivated by issues of saving energy in data centers we define a collection of new problems referred to as "machine activation" problems. The central framework we introduce considers a collection of $m$ machines (unrelated or related) with each machine $i$ having an {\em activation cost} of $a_i$. There is also a collection of $n$ jobs that need to be performed, and $p_{i,j}$ is the processing time of job $j$ on machine $i$. We assume that there is an activation cost budget of $A$ -- we would like to {\em select} a subset $S$ of the machines to activate with total cost $a(S) \le A$ and {\em find} a schedule for the $n$ jobs on the machines in $S$ minimizing the makespan (or any other metric). For the general unrelated machine activation problem, our main results are that if there is a schedule with makespan $T$ and activation cost $A$ then we can obtain a schedule with makespan $\makespanconstant T$ and activation cost $\costconstant A$, for any $\epsilon >0$. We also consider assignment costs for jobs as in the generalized assignment problem, and using our framework, provide algorithms that minimize the machine activation and the assignment cost simultaneously. In addition, we present a greedy algorithm which only works for the basic version and yields a makespan of $2T$ and an activation cost $A (1+\ln n)$. For the uniformly related parallel machine scheduling problem, we develop a polynomial time approximation scheme that outputs a schedule with the property that the activation cost of the subset of machines is at most $A$ and the makespan is at most $(1+\epsilon) T$ for any $\epsilon >0$. | [
"Computer Science Archive->cs.CC",
"Computer Science Archive->cs.DS"
]
| 2009-12-07T20:24:24Z |
1810.07237 | A Retrieval Framework and Implementation for Electronic Documents with Similar Layouts | As the number of digital documents requiring investigation increases, it has become more important to identify relevant documents to a given case. There have been continual demands for finding relevant files in order to overcome this kind of issues. Regarding finding similar files, there can be a situation where there is no available metadata such as timestamp, file size, title, subject, template, author, etc. In this situation, investigators will focus on searching document files having specific keywords related to a given case. Although the traditional keyword search with elaborate regular expressions is useful for digital forensics, there is a possibility that closely related documents are missing because they have totally different body contents. In this paper, we introduce a recent actual case on handling large amounts of document files. This case suggests that similar layout search will be useful for more efficient digital investigations if it can be utilized appropriately for supplementing results of the traditional keyword search. Until now, research involving electronic-document similarity has mainly focused on byte streams, format structures and body contents. However, there has been little research on the similarity of visual layouts from the viewpoint of digital forensics. In order to narrow this gap, this study demonstrates a novel framework for retrieving electronic document files having similar layouts, and implements a tool for finding similar Microsoft OOXML files using user-controlled layout queries based on the framework. | [
"Computer Science Archive->cs.IR"
]
| 2018-10-16T19:10:50Z |
hep-th/0611270 | Particle-like solutions to the Yang--Mills-dilaton system in d=4+1 dimensions | We construct static solutions to a SU(2) Yang--Mills (YM) dilaton model in 4+1 dimensions subject to bi-azimuthal symmetry. The YM sector of the model consists of the usual YM term and the next higher order term of the YM hierarchy, which is required by the scaling condition for the existence of finite energy solutions. The basic features of two different types of configurations are studied, corresponding to (multi)solitons with topological charge $n^2$, and soliton--antisoliton pairs with zero topological charge. | [
"Physics Archive->hep->hep-th"
]
| 2006-11-24T16:46:43Z |
1212.2793 | Demonstration of zero optical backscattering from single nanoparticles | We present the first experimental demonstration of zero backscattering from nanoparticles at op- tical frequencies as originally discussed by Kerker et. al. [M. Kerker, D. Wang, and C. Giles, J. Opt. Soc. A 73, 765 (1983)]. GaAs pillars were fabricated on a fused silica substrate and the spectrum of the backscattered radiation was measured in the wavelength range 600-1000 nm. Suppression of backscattering occurred at ~725 nm, agreeing with calculations based on the discrete dipole approximation. Particles with zero backscattering provide new functionality for metamaterials and optical antennas. | [
"Physics Archive->cond-mat->cond-mat.mes-hall",
"Physics Archive->physics->physics.optics"
]
| 2012-12-12T12:36:44Z |
2105.06762 | DialogSum: A Real-Life Scenario Dialogue Summarization Dataset | Proposal of large-scale datasets has facilitated research on deep neural models for news summarization. Deep learning can also be potentially useful for spoken dialogue summarization, which can benefit a range of real-life scenarios including customer service management and medication tracking. To this end, we propose DialogSum, a large-scale labeled dialogue summarization dataset. We conduct empirical analysis on DialogSum using state-of-the-art neural summarizers. Experimental results show unique challenges in dialogue summarization, such as spoken terms, special discourse structures, coreferences and ellipsis, pragmatics and social common sense, which require specific representation learning technologies to better deal with. | [
"Computer Science Archive->cs.AI",
"Computer Science Archive->cs.CL"
]
| 2021-05-14T11:12:40Z |
hep-th/0109222 | The Three-Dimensional Noncommutative Nonlinear Sigma Model in Superspace | We study the superspace formulation of the noncommutative nonlinear supersymmetric O(N) invariant sigma-model in 2+1 dimensions. We prove that the model is renormalizable to all orders of 1/N and explicitly verify that the model is asymptotically free. | [
"Physics Archive->hep->hep-th"
]
| 2001-09-28T18:01:49Z |
2312.06803 | Tearing down spacetime with quantum disentanglement | A longstanding enigma within AdS/CFT concerns the entanglement entropy of holographic quantum fields in Rindler space. The vacuum of a quantum field in Minkowski spacetime can be viewed as an entangled thermofield double of two Rindler wedges at a temperature $T=1/2\pi$. We can gradually disentangle the state by lowering this temperature, and the entanglement entropy should vanish in the limit $T\to 0$ to the Boulware vacuum. However, holography yields a non-zero entanglement entropy at arbitrarily low $T$, since the bridge in the bulk between the two wedges retains a finite width. We show how this is resolved by bulk quantum effects of the same kind that affect the entropy of near-extremal black holes. Specifically, a Weyl transformation maps the holographic Boulware states to near-extremal hyperbolic black holes. A reduction to an effective two-dimensional theory captures the large quantum fluctuations in the geometry of the bridge, which bring down to zero the density of entangled states in the Boulware vacuum. | [
"Physics Archive->hep->hep-th"
]
| 2023-12-11T19:27:12Z |
1206.3392 | Secure Compute-and-Forward in a Bidirectional Relay | We consider the basic bidirectional relaying problem, in which two users in a wireless network wish to exchange messages through an intermediate relay node. In the compute-and-forward strategy, the relay computes a function of the two messages using the naturally-occurring sum of symbols simultaneously transmitted by user nodes in a Gaussian multiple access (MAC) channel, and the computed function value is forwarded to the user nodes in an ensuing broadcast phase. In this paper, we study the problem under an additional security constraint, which requires that each user's message be kept secure from the relay. We consider two types of security constraints: perfect secrecy, in which the MAC channel output seen by the relay is independent of each user's message; and strong secrecy, which is a form of asymptotic independence. We propose a coding scheme based on nested lattices, the main feature of which is that given a pair of nested lattices that satisfy certain "goodness" properties, we can explicitly specify probability distributions for randomization at the encoders to achieve the desired security criteria. In particular, our coding scheme guarantees perfect or strong secrecy even in the absence of channel noise. The noise in the channel only affects reliability of computation at the relay, and for Gaussian noise, we derive achievable rates for reliable and secure computation. We also present an application of our methods to the multi-hop line network in which a source needs to transmit messages to a destination through a series of intermediate relays. | [
"Computer Science Archive->cs.IT",
"Mathematics Archive->math.IT"
]
| 2012-06-15T08:08:09Z |
1703.07917 | Distribution of captured planetesimals in circumplanetary gas disks and implications for accretion of regular satellites | Regular satellites of giant planets are formed by accretion of solid bodies in circumplanetary disks. Planetesimals that are moving on heliocentric orbits and are sufficiently large to be decoupled from the flow of the protoplanetary gas disk can be captured by gas drag from the circumplanetary disk. In the present work, we examine the distribution of captured planetesimals in circumplanetary disks using orbital integrations. We find that the number of captured planetesimals reaches an equilibrium state as a balance between continuous capture and orbital decay into the planet. The number of planetesimals captured into retrograde orbits is much smaller than those on prograde orbits, because the former ones experience strong headwind and spiral into the planet rapidly. We find that the surface number density of planetesimals at the current radial location of regular satellites can be significantly enhanced by gas drag capture, depending on the velocity dispersions of planetesimals and the width of the gap in the protoplanetary disk. Using a simple model, we also examine the ratio of the surface densities of dust and captured planetesimals in the circumplanetary disk, and find that solid material at the current location of regular satellites can be dominated by captured planetesimals when the velocity dispersion of planetesimals is rather small and a wide gap is not formed in the protoplanetary disk. In this case, captured planetesimals in such a region can grow by mutual collision before spiraling into the planet, and would contribute to the growth of regular satellites. | [
"Physics Archive->astro-ph->astro-ph.EP"
]
| 2017-03-23T03:25:37Z |
1310.6300 | Bell-type inequality and quantum nonlocality in four-qubit systems | We present a Bell-type inequality for four-qubit systems. Using the inequality we investigate quantum nonlocality of a generic family of states $\left|G_{abcd}\right >$ [Phys. Rev. A 65, 052112 (2002)] and several canonical four-qubit entangled states. It has been demonstrated that the inequality is maximally violated by so called "four-qubit maximal entangled state $\left|G_{m}\right >$" and it is also violated by the four-qubit W state and a special family of states $\left|G_{ab00}\right >$. Moreover, a useful entanglement-nonlocality relationship for the family of states $\left|G_{ab00}\right >$ is obtained. | [
"Physics Archive->quant-ph"
]
| 2013-10-23T17:23:49Z |
0901.4304 | Weakly coupled discretized gravity | We consider discretized gravity in 4+2 dimensions compactified on a disk of constant negative curvature. The curvature of the disk avoids the presence of dangerous ultra-light scalar modes but comes also along with a high multiplicity of states potentially jeopardizing a good strong-coupling behavior of the discretized theory. We demonstrate that for Standard Model matter propagating on the five-dimensional boundary submanifold of the disk, the strong coupling scale, as seen by an observer, can be parametrically larger than the local Planck scale. As a consequence, we obtain a description of weakly coupled discretized gravity on the boundary that can be compared with the continuum theory all the way up to the effective five-dimensional Planck scale. | [
"Physics Archive->hep->hep-ph",
"Physics Archive->hep->hep-th"
]
| 2009-01-27T18:16:49Z |
hep-lat/0008001 | SU(2) gluon propagator on a coarse anisotropic lattice | We calculated the SU(2) gluon propagator in Landau gauge on an anisotropic coarse lattice with the improved action. The standard and the improved scheme are used to fix the gauge in this work. Even on the coarse lattice the lattice gluon propagator can be well described by a function of the continuous momentum. The effect of the improved gauge fixing scheme is found not to be apparent. Based on the Marenzoni's model, the mass scale and the anomalous dimension are extracted and can be reasonably extrapolated to the continuum limit with the values $\alpha\sim 0.3$ and $M\sim 600MeV$. We also extract the physical anisotropy $\xi$ from the gluon propagator due to the explicit $\xi$ dependence of the gluon propagator. | [
"Physics Archive->hep->hep-lat"
]
| 2000-08-02T06:31:00Z |
1707.08246 | Evidence of Eta Aquariid Outbursts Recorded in the Classic Maya Hieroglyphic Script Using Orbital Integrations | No firm evidence has existed that the ancient Maya civilization recorded specific occurrences of meteor showers or outbursts in the corpus of Maya hieroglyphic inscriptions. In fact, there has been no evidence of any pre-Hispanic civilization in the Western Hemisphere recording any observations of any meteor showers on any specific dates. The authors numerically integrated meteoroid-sized particles released by Comet Halley as early as 1404 BC to identify years within the Maya Classic Period, AD 250-909, when Eta Aquariid outbursts might have occurred. Outbursts determined by computer model were then compared to specific events in the Maya record to see if any correlation existed between the date of the event and the date of the outburst. The model was validated by successfully explaining several outbursts around the same epoch in the Chinese record. Some outbursts observed by the Maya were due to recent revolutions of Comet Halley, within a few centuries, and some to resonant behavior in older Halley trails, of the order of a thousand years. Examples were found of several different Jovian mean motion resonances as well as the 1:3 Saturnian resonance that have controlled the dynamical evolution of meteoroids in apparently observed outbursts. | [
"Physics Archive->astro-ph->astro-ph.EP"
]
| 2017-07-25T23:08:26Z |
0903.4802 | Instability of the Rayleigh-Jeans spectrum in weak wave turbulence theory | We study the four-wave kinetic equation of weak turbulence linearized around the Rayleigh-Jeans spectrum when the collision integral is associated with short-range interactions between non-relativistic bosonic quasiparticles. The technique used for the analysis of the stability is based on the properties of the Mellin transform of the kernel in the integral equation. We find that any perturbation of the Rayleigh-Jeans distribution evolves towards low momentum scales in such a form that, when $t \to \infty$, all the particles occupy a sphere of radius arbitrary small. | [
"Physics Archive->cond-mat->cond-mat.stat-mech"
]
| 2009-03-27T14:15:25Z |
2011.09160 | Relieve the $H_0$ tension with a new coupled generalized three-form dark energy model | In this work we propose a new coupled generalized three-form dark energy model, in which dark energy are represented by a three-form field and other components are represented by ideal fluids. We first perform a dynamical analysis on the new model and obtain four fixed points, including a saddle point representing a radiation dominated Universe, a saddle point representing a matter dominated Universe, and two attractors representing two dark energy dominated Universes. We then use the observational data, including cosmic microwave background (CMB) data, baryon acoustic oscillations (BAO) data, and Type Ia supernovae (SN Ia) data to constrain the model parameters of the coupled generalized three-form dark energy model. For comparison, we also consider the coupled three-form dark energy model, generalized three-form dark energy model, and $\Lambda$CDM model, we find that the coupled generalized three-form dark energy model is the only one model that can reduce the $H_0$ tension to a more acceptable level, with $H_0=70.1_{-1.5}^{+1.4}$ km/s/Mpc, which is consistent with R19 at $2.0\sigma$ confidence level. We also investigate the best-fit dynamical behavior of the coupled generalized three-form dark energy model, and show that our model is equivalent to a quintom dark energy model, in which dark energy, at early epoch, behaves like some form of early dark energy with a small positive equation of state. | [
"Physics Archive->astro-ph->astro-ph.CO"
]
| 2020-11-18T09:00:04Z |
1801.07992 | XZero: On Practical Cross-Technology Interference-Nulling for LTE-U/WiFi Coexistence | LTE-U/WiFi coexistence can be significantly improved by placing so-called coexistence gaps in space through cross-technology interference-nulling (CTIN) from LTE-U BS towards WiFi nodes. Such coordinated co-existence scheme requires, for the exchange of control messages, a cross-technology control channel (CTC) between LTE-U and WiFi networks which was presented recently. However, it is unclear how a practical CTIN operates in the absence of channel state information which is needed for CTIN but cannot be obtained from the CTC. We present XZero, the first practical CTIN system that is able to quickly find the suitable precoding configuration used for interference nulling without having to search the whole space of angular orientations. XZero performs a tree-based search to find the direction for the null beam(s) by exploiting the feedback received from the WiFi AP on the tested null directions. We have implemented a prototype of XZero using SDR platform for LTE-U and commodity hardware for WiFi and evaluated its performance in a large indoor testbed. Evaluation results reveal on average a reduction by 15.7 dB in interference-to-noise ratio at the nulled WiFi nodes when using a ULA with four antennas. Moreover, XZero has a sub-second reconfiguration delay which is up to 10x smaller as compared to naive exhaustive linear search. | [
"Computer Science Archive->cs.NI"
]
| 2018-01-24T14:08:13Z |
1410.0405 | Linearly Solvable Stochastic Control Lyapunov Functions | This paper presents a new method for synthesizing stochastic control Lyapunov functions for a class of nonlinear stochastic control systems. The technique relies on a transformation of the classical nonlinear Hamilton-Jacobi-Bellman partial differential equation to a linear partial differential equation for a class of problems with a particular constraint on the stochastic forcing. This linear partial differential equation can then be relaxed to a linear differential inclusion, allowing for relaxed solutions to be generated using sum of squares programming. The resulting relaxed solutions are in fact viscosity super/subsolutions, and by the maximum principle are pointwise upper and lower bounds to the underlying value function, even for coarse polynomial approximations. Furthermore, the pointwise upper bound is shown to be a stochastic control Lyapunov function, yielding a method for generating nonlinear controllers with pointwise bounded distance from the optimal cost when using the optimal controller. These approximate solutions may be computed with non-increasing error via a hierarchy of semidefinite optimization problems. Finally, this paper develops a-priori bounds on trajectory suboptimality when using these approximate value functions, as well as demonstrates that these methods, and bounds, can be applied to a more general class of nonlinear systems not obeying the constraint on stochastic forcing. Simulated examples illustrate the methodology. | [
"Mathematics Archive->math.OC"
]
| 2014-10-01T22:49:18Z |
quant-ph/0512049 | On the conection between the Liouville equation and the Schrodinger equation | We derive a classical Schrodinger type equation from the classical Liouville equation in phase space. The derivation is based on a Wigner type Fourier transform of the classical phase space probability distribution, which depends on an arbitrary constant $\alpha$ with dimension of action. In order to achieve this goal two requirements are necessary: 1) It is assumed that the classical probability amplitude $\Psi(x,t)$ can be expanded in a complete set of functions $\Phi_n(x)$ defined in the configuration space; 2) the classical phase space distribution $W(x,p,t)$ obeys the Liouville equation and is a real function of the position, the momentum and the time. We show that the constant $\alpha$ appearing in the Fourier transform of the classical phase space distribution, and also in the classical Schrodinger type equation, has its origin in the spectral distribution of the vacuum zero-point radiation, and is identified with the Planck's constant $\hbar$. | [
"Physics Archive->quant-ph"
]
| 2005-12-06T18:57:14Z |
1904.02560 | The Minimal Simple Composite Higgs Model | Most of the analysis of composite Higgs have focussed on the Minimal Composite Higgs Model, based on the coset SO(5)$\times$U(1)$_X$/SO(4)$\times$U(1)$_X$. We consider a model based on the coset of simple groups SO(7)/SO(6), with SO(4)$\times$U(1)$_X$ embedded into SO(6). This extension of the minimal model leads to a new complex pNGB that has hypercharge and is a singlet of SU(2)$_L$, with properties mostly determined by the pattern of symmetry breaking and a mass of order TeV. Composite electroweak unification also leads to new bosonic and fermion resonances with exotic charges, not present in the minimal model. The lightest of these resonances is stable, and in some cases could provide candidates for dark matter. A new rich phenomenology is expected at LHC. | [
"Physics Archive->hep->hep-ph"
]
| 2019-04-04T14:04:42Z |
0902.2348 | Electromagnetic meson form factor from a relativistic coupled-channel approach | Point-form relativistic quantum mechanics is used to derive an expression for the electromagnetic form factor of a pseudoscalar meson for space-like momentum transfers. The elastic scattering of an electron by a confined quark-antiquark pair is treated as a relativistic two-channel problem for the $q\bar{q}e$ and $q\bar{q}e\gamma$ states. With the approximation that the total velocity of the $q\bar{q}e$ system is conserved at (electromagnetic) interaction vertices this simplifies to an eigenvalue problem for a Bakamjian-Thomas type mass operator. After elimination of the $q\bar{q}e\gamma$ channel the electromagnetic meson current and form factor can be directly read off from the one-photon-exchange optical potential. By choosing the invariant mass of the electron-meson system large enough, cluster separability violations become negligible. An equivalence with the usual front-form expression, resulting from a spectator current in the $q^+=0$ reference frame, is established. The generalization of this multichannel approach to electroweak form factors for an arbitrary bound few-body system is quite obvious. By an appropriate extension of the Hilbert space this approach is also able to accommodate exchange-current effects. | [
"Physics Archive->nucl->nucl-th"
]
| 2009-02-13T17:08:21Z |
1511.07289 | Fast and Accurate Deep Network Learning by Exponential Linear Units (ELUs) | We introduce the "exponential linear unit" (ELU) which speeds up learning in deep neural networks and leads to higher classification accuracies. Like rectified linear units (ReLUs), leaky ReLUs (LReLUs) and parametrized ReLUs (PReLUs), ELUs alleviate the vanishing gradient problem via the identity for positive values. However, ELUs have improved learning characteristics compared to the units with other activation functions. In contrast to ReLUs, ELUs have negative values which allows them to push mean unit activations closer to zero like batch normalization but with lower computational complexity. Mean shifts toward zero speed up learning by bringing the normal gradient closer to the unit natural gradient because of a reduced bias shift effect. While LReLUs and PReLUs have negative values, too, they do not ensure a noise-robust deactivation state. ELUs saturate to a negative value with smaller inputs and thereby decrease the forward propagated variation and information. Therefore, ELUs code the degree of presence of particular phenomena in the input, while they do not quantitatively model the degree of their absence. In experiments, ELUs lead not only to faster learning, but also to significantly better generalization performance than ReLUs and LReLUs on networks with more than 5 layers. On CIFAR-100 ELUs networks significantly outperform ReLU networks with batch normalization while batch normalization does not improve ELU networks. ELU networks are among the top 10 reported CIFAR-10 results and yield the best published result on CIFAR-100, without resorting to multi-view evaluation or model averaging. On ImageNet, ELU networks considerably speed up learning compared to a ReLU network with the same architecture, obtaining less than 10% classification error for a single crop, single model network. | [
"Computer Science Archive->cs.LG"
]
| 2015-11-23T15:58:05Z |
1903.11523 | Chaotic and turbulent mixing of passive scalar | Spatio-temporal deterministic chaos at small Taylor-Reynolds numbers $Re_{\lambda} \lesssim 40$ and distributed chaos at turbulent $Re_{\lambda} \gtrsim 40$ in passive scalar dynamics have been studied using results of direct numerical simulations of homogeneous incompressible flows (with and without mean gradient of the passive scalar) for $8 \leq Re_{\lambda} < 700$ and of a reacting turbulent mixing layer. It is shown that the deterministic chaos in the passive scalar fluctuations at the small $Re_{\lambda}$ is characterized by exponential spatial (wavenumber) spectrum: $E(k) \propto \exp-(k/k_c)$, whereas the distributed chaos at turbulent $Re_{\lambda}$ is characterized by stretched exponential spectrum $E(k) \propto \exp-(k/k_{\beta})^{3/4}$. The Birkhoff-Saffman invariant related to the momentum conservation and, due to the Noether theorem, to the spatial homogeneity has been used as a theoretical basis for this stretched exponential spectrum. Although the $k_c$ and $k_{\beta}$ represent the large-scale structures a relevance of the Batchelor scale $k_{bat}$ has been established as well: the normalized values $k_c/k_{bat}$ and $k_{\beta}/k_{bat}$ exhibit universality. | [
"Physics Archive->physics->physics.flu-dyn"
]
| 2019-03-27T16:19:01Z |
0911.0226 | Student experiences of virtual reality - a case study in learning special relativity | We present a study of student learning through the use of virtual reality. A software package is used to introduce concepts of special relativity to students in a game-like environment where users experience the effects of travelling at near light speeds. From this new perspective, space and time are significantly different to that experienced in everyday life. The study explores how students have worked with this environment and how these students have used this experience in their study of special relativity. A mixed method approach has been taken to evaluate the outcomes of separate implementations of the package at two universities. Students found the simulation to be a positive learning experience and described the subject area as being less abstract after its use. Also, students were more capable of correctly answering concept questions relating to special relativity, and a small but measurable improvement was observed in the final exam. | [
"Physics Archive->physics->physics.ed-ph"
]
| 2009-11-02T02:06:49Z |
2312.04875 | MVDD: Multi-View Depth Diffusion Models | Denoising diffusion models have demonstrated outstanding results in 2D image generation, yet it remains a challenge to replicate its success in 3D shape generation. In this paper, we propose leveraging multi-view depth, which represents complex 3D shapes in a 2D data format that is easy to denoise. We pair this representation with a diffusion model, MVDD, that is capable of generating high-quality dense point clouds with 20K+ points with fine-grained details. To enforce 3D consistency in multi-view depth, we introduce an epipolar line segment attention that conditions the denoising step for a view on its neighboring views. Additionally, a depth fusion module is incorporated into diffusion steps to further ensure the alignment of depth maps. When augmented with surface reconstruction, MVDD can also produce high-quality 3D meshes. Furthermore, MVDD stands out in other tasks such as depth completion, and can serve as a 3D prior, significantly boosting many downstream tasks, such as GAN inversion. State-of-the-art results from extensive experiments demonstrate MVDD's excellent ability in 3D shape generation, depth completion, and its potential as a 3D prior for downstream tasks. | [
"Computer Science Archive->cs.CV"
]
| 2023-12-08T07:16:09Z |
1102.4445 | Directional correlations in quantum walks with two particles | Quantum walks on the line with a single particle possess a classical analog. Involving more walkers opens up the possibility to study collective quantum effects, such as many particle correlations. In this context, entangled initial states and indistinguishability of the particles play a role. We consider directional correlations between two particles performing a quantum walk on a line. For non-interacting particles we find analytic asymptotic expressions and give the limits of directional correlations. We show that introducing $\delta$-interaction between the particles, one can exceed the limits for non-interacting particles. | [
"Physics Archive->quant-ph"
]
| 2011-02-22T10:23:22Z |
1308.6034 | Microsegregation and dendritic growth mode of Al-5wt%Cu alloy based on non-equilibrium mush zone model | The microsegregation and dendritic growth mode of Al-5wt%Cu alloy was investigated. In the early solidification stage, the crystal growth mode of interrupted growth and periodic boundary trapping will happen, which results in the segregationless dendritic grains. Microsegregation only exists at the final solidification stage with extremely tiny residual melt fraction. In the tiny residual melt zone, the diffusion of solute from the enriched boundary layer to the residual melt and the convergence of enriched boundaries produce the final microsegregation. | [
"Physics Archive->cond-mat->cond-mat.mtrl-sci"
]
| 2013-08-28T02:34:11Z |
1501.02070 | Evidence for enhanced persistent emission during sub-Eddington thermonuclear bursts | The standard approach for time-resolved X-ray spectral analysis of thermonuclear bursts involves subtraction of the pre-burst emission as background. This approach implicitly assumes that the persistent flux remains constant throughout the burst. We reanalyzed 332 photospheric radius expansion bursts observed from 40 sources by the Rossi X-ray Timing Explorer, introducing a multiplicative factor $f_a$ to the persistent emission contribution in our spectral fits. We found that for the majority of spectra the best-fit value of $f_a$ is significantly greater than 1, suggesting that the persistent emission typically increases during a burst. Elevated $f_a$ values were not found solely during the radius expansion interval of the burst, but were also measured in the cooling tail. The modified model results in a lower average value of the $\chi^2$ fit statistic, indicating superior spectral fits, but not yet to the level of formal statistical consistency for all the spectra. We interpret the elevated $f_a$ values as an increase of the mass accretion rate onto the neutron star during the burst, likely arising from the effects of Poynting-Robertson drag on the disk material. We measured an inverse correlation of $f_a$ with the persistent flux, consistent with theoretical models of the disc response. We suggest that this modified approach may provide more accurate burst spectral parameters, as well as offering a probe of the accretion disk structure. | [
"Physics Archive->astro-ph->astro-ph.HE"
]
| 2015-01-09T09:08:59Z |
1312.3429 | Unsupervised learning of depth and motion | We present a model for the joint estimation of disparity and motion. The model is based on learning about the interrelations between images from multiple cameras, multiple frames in a video, or the combination of both. We show that learning depth and motion cues, as well as their combinations, from data is possible within a single type of architecture and a single type of learning algorithm, by using biologically inspired "complex cell" like units, which encode correlations between the pixels across image pairs. Our experimental results show that the learning of depth and motion makes it possible to achieve state-of-the-art performance in 3-D activity analysis, and to outperform existing hand-engineered 3-D motion features by a very large margin. | [
"Computer Science Archive->cs.CV",
"Computer Science Archive->cs.LG",
"Statistics Archive->stat.ML"
]
| 2013-12-12T10:03:47Z |
2309.05110 | An introduction to the parton and hadron cascade model PACIAE 3.0 | We introduce a parton and hadron cascade model PACIAE 3.0 based on PYTHIA 6.428 and the PACIAE 2.2 program series. The simulation framework of C-, B-, and A-loops are designed for the high energy ($\sqrt{s_{NN}}\geq 3$ GeV) and low energy ($\sqrt{s_{NN}}<3$ GeV) nuclear collisions, respectively, in PACIAE 3.0. In the C-loop simulation, the parton-parton inelastic scattering processes are added in the partonic rescattering process. The single string structure and multiple string interaction mechanism have been introduced investigating the strangeness enhancement in C- and B-loop. An improved mapping relation between the centrality percentage definition and the impact parameter definition is proposed responding the observation of $b_{max}\approx 20$ fm from ALICE, ATLAS, and CMS collaborations. We have extensively modified the phenomenological coalescence hadronization model. The PACIAE 3.0 model simulated results of particle yield, transverse momentum distribution, and rapidity distribution well reproduce, respectively, the experimental data measured at FOPI, E895, RHIC, and LHC energies. | [
"Physics Archive->hep->hep-ph",
"Physics Archive->nucl->nucl-th"
]
| 2023-09-10T18:34:05Z |
1302.4493 | Modified Hamilton formalism for fields | In Hamiltonian mechanics the equations of motion may be considered as a condition on the tangent vectors to the solution; they should be null-vectors of the symplictic structure. Usually the formalism for the field case is done by replacing the finite dimensional configuration space by an infinite dimensional one. In the present paper we work in worldsheet-targetspace formalism. The null-vectors of symplectic 2-form are replaced by null-polyvectors of a higher rank form on a finite dimensional manifold. The action in this case is an integral of a differential form over a surface in phase space. The method to obtain such a description from the Lagrange formalism generalizes the Legendre transformation. The requirement for this transformation to preserve the value of the action and its extremality leads to a natural definition of this procedure. | [
"Mathematics Archive->math.MP",
"Physics Archive->hep->hep-th",
"Physics Archive->math-ph"
]
| 2013-02-19T00:47:53Z |
1701.07838 | Cosmic evolution of stellar quenching by AGN feedback: clues from the Horizon-AGN simulation | The observed massive end of the galaxy stellar mass function is steeper than its predicted dark matter halo counterpart in the standard $\Lambda $CDM paradigm. In this paper, we investigate the impact of active galactic nuclei (AGN) feedback on star formation in massive galaxies. We isolate the impact of AGNs by comparing two simulations from the HORIZON suite, which are identical except that one also includes super massive black holes (SMBH), and related feedback models. This allows us to cross-identify individual galaxies between simulations and quantify the effect of AGN feedback on their properties, including stellar mass and gas outflows. We find that massive galaxies ($ \rm M_{*} \geq 10^{11} M_\odot $) are quenched by AGN feedback to the extent that their stellar masses decrease by up to 80% at $z=0$. SMBHs affect their host halo through a combination of outflows that reduce their baryonic mass, particularly for galaxies in the mass range $ \rm 10^9 M_\odot \leq M_{*} \leq 10^{11} M_\odot $, and a disruption of central gas inflows, which limits in-situ star formation. As a result, net gas inflows onto massive galaxies, $ \rm M_{*} \geq 10^{11} M_\odot $, drop by up to 70%. We measure a redshift evolution in the stellar mass ratio of twin galaxies with and without AGN feedback, with galaxies of a given stellar mass showing stronger signs of quenching earlier on. This evolution is driven by a progressive flattening of the $\rm M_{\rm SMBH}-M_* $ relation with redshift, particularly for galaxies with $\rm M_{*} \leq 10^{10} M_\odot $. $\rm M_{\rm SMBH}/M_*$ ratios decrease over time, as falling average gas densities in galaxies curb SMBH growth. | [
"Physics Archive->astro-ph->astro-ph.GA",
"Physics Archive->astro-ph->astro-ph.HE"
]
| 2017-01-26T19:00:25Z |
2203.07292 | Hyperbolic Topological Band Insulators | Recently, hyperbolic lattices that tile the negatively curved hyperbolic plane emerged as a new paradigm of synthetic matter, and their energy levels were characterized by a band structure in a four- (or higher-)dimensional momentum space. To explore the uncharted topological aspects arising in hyperbolic band theory, we here introduce elementary models of hyperbolic topological band insulators: the hyperbolic Haldane model and the hyperbolic Kane-Mele model; both obtained by replacing the hexagonal cells of their Euclidean counterparts by octagons. Their non-trivial topology is revealed by computing topological invariants in both position and momentum space. The bulk-boundary correspondence is evidenced by comparing bulk and boundary density of states, by modelling propagation of edge excitations, and by their robustness against disorder. | [
"Physics Archive->cond-mat->cond-mat.mes-hall",
"Physics Archive->cond-mat->cond-mat.other"
]
| 2022-03-14T17:01:33Z |
hep-ph/0605280 | Relic abundance of dark matter in the minimal universal extra dimension model | We investigate the relic abundance of dark matter in the minimal universal extra dimension model including resonance processes by second Kaluza-Klein (KK) particles in all coannihilation processes. After including second KK resonance processes, the relic abundance of dark matter is reduced by about 30%. Thus, the compactification scale 1/R of the extra dimension consistent with the WMAP observation is increased by a few hundred GeV. As a result, the cosmologically allowed compactification scale is 600 GeV < 1/R < 1400 GeV for Lambda R = 20. | [
"Physics Archive->hep->hep-ph"
]
| 2006-05-26T05:34:27Z |
0802.2187 | General Notion of Curvature in Catastrophe Theory Terms | We introduce a new notion of a curvature of a superconnection, different from the one obtained by a purely algebraic analogy with the curvature of a linear connection. The naturalness of this new notion of a curvature of a superconnection comes from the study of singularities of smooth sections of vector bundles (Catastrophe Theory). We demonstrate that the classical examples of obstructions to a local equivalence: exterior differential for 2-forms, Riemannian tensor, Weil tensor, curvature of a linear connection and Nijenhuis tensor can be treated in terms of one general approach. This approach, applied to the superconnection leads to a new notion of a curvature (proposed in this paper) of a superconnection. | [
"Mathematics Archive->math.MP",
"Physics Archive->math-ph"
]
| 2008-02-15T17:15:10Z |
1407.4575 | Correlations of alpha-particles in splitting of C-12 nuclei by neutrons of energy of 14.1 MeV | Correlations of $\alpha$-particles are studied on statistics of 400 events of splitting $^{12}$C $\rightarrow$ 3$\alpha$ in nuclear track emulsion exposed to $14.1 MeV$ neutrons. The ranges and emission angles of the $\alpha$-particles are measured. Distributions over energy of $\alpha$-particle pairs and triples are obtained. | [
"Physics Archive->nucl->nucl-ex"
]
| 2014-07-17T06:37:26Z |
hep-th/0003093 | Comments on Instantons on Noncommutative R^4 | We study U(1) and U(2) instanton solutions on noncommutative R^4 based on the noncommutative version of ADHM equation proposed by Nekrasov and Schwarz. It is shown that the anti-self-dual gauge fields on self-dual noncommutative R^4 correctly give integer instanton numbers for all cases we consider. We also show that the completeness relation in the ADHM construction is generally satisfied even for noncommutative spaces. | [
"Physics Archive->hep->hep-th"
]
| 2000-03-13T09:28:37Z |
1703.07998 | Transformation properties and entanglement of relativistic qubits under space-time and gauge transformations | We revisit the properties of qubits under Lorentz transformations and, by considering Lorentz invariant quantum states in the Heisenberg formulation, clarify some misleading notation that has appeared in the literature on relativistic quantum information theory. We then use this formulation to consider the transformation properties of qubits and density matrices under space-time and gauge transformations. Finally we use our results to understand the behaviour of entanglement between different partitions of quantum systems. Our approach not only clarifies the notation, but provides a more intuitive and simple way of gaining insight into the behaviour of relativistic qubits. In particular, it allows us to greatly generalize the results in the current literature as well as substantially simplifying the calculations that are needed. | [
"Physics Archive->quant-ph"
]
| 2017-03-23T10:59:18Z |
1412.8687 | The Mass of Kepler-93b and The Composition of Terrestrial Planets | Kepler-93b is a 1.478 +/- 0.019 Earth radius planet with a 4.7 day period around a bright (V=10.2), astroseismically-characterized host star with a mass of 0.911+/-0.033 solar masses and a radius of 0.919+/-0.011 solar radii. Based on 86 radial velocity observations obtained with the HARPS-N spectrograph on the Telescopio Nazionale Galileo and 32 archival Keck/HIRES observations, we present a precise mass estimate of 4.02+/-0.68 Earth masses. The corresponding high density of 6.88+/-1.18 g/cc is consistent with a rocky composition of primarily iron and magnesium silicate. We compare Kepler-93b to other dense planets with well-constrained parameters and find that between 1-6 Earth masses, all dense planets including the Earth and Venus are well-described by the same fixed ratio of iron to magnesium silicate. There are as of yet no examples of such planets with masses > 6 Earth masses: All known planets in this mass regime have lower densities requiring significant fractions of volatiles or H/He gas. We also constrain the mass and period of the outer companion in the Kepler-93 system from the long-term radial velocity trend and archival adaptive optics images. As the sample of dense planets with well-constrained masses and radii continues to grow, we will be able to test whether the fixed compositional model found for the seven dense planets considered in this paper extends to the full population of 1-6 Earth mass planets. | [
"Physics Archive->astro-ph->astro-ph.EP",
"Physics Archive->astro-ph->astro-ph.SR"
]
| 2014-12-30T17:02:41Z |
1610.03719 | Backward stochastic differential equations with Young drift | We prove via a direct fixpoint argument the well-posedness of backward stochastic differential equations containing an additional drift driven by a path of finite $p$-variation with $p \in [1,2)$. An application to the Feynman-Kac representation of semilinear rough partial differential equations is given. | [
"Mathematics Archive->math.PR"
]
| 2016-10-12T14:12:23Z |
1511.04053 | Visualizing the Process of Process Modeling with PPMCharts | In the quest for knowledge about how to make good process models, recent research focus is shifting from studying the quality of process models to studying the process of process modeling (often abbreviated as PPM) itself. This paper reports on our efforts to visualize this specific process in such a way that relevant characteristics of the modeling process can be observed graphically. By recording each modeling operation in a modeling process, one can build an event log that can be used as input for the PPMChart Analysis plug-in we implemented in ProM. The graphical representation this plug-in generates allows for the discovery of different patterns of the process of process modeling. It also provides different views on the process of process modeling (by configuring and filtering the charts). | [
"Computer Science Archive->cs.SE"
]
| 2015-11-11T17:40:41Z |
1406.0215 | Cognitive Coordination of Global Service Delivery | Formal coordination mechanisms are of growing importance as human-based service delivery becomes more globalized and informal mechanisms are no longer effective. Further it is becoming apparent that business environments, communication among distributed teams, and work performance are all subject to endogenous and exogenous uncertainty. This paper describes a stochastic model of service requests in global service delivery and then puts forth a cognitive approach for coordination in the face of uncertainty, based on a perception-action loop and receding horizon control. Optimization algorithms used are a mix of myopic dynamic programming and constraint-based programming. The coordination approach described has been deployed by a globally integrated enterprise in a very large-scale global delivery system and has been demonstrated to improve work efficiency by 10-15% as compared to manual planning. | [
"Computer Science Archive->cs.OH"
]
| 2014-06-01T23:12:06Z |
2108.05817 | Hong Kong Air Traffic: Explanation and Prediction based on Sparse Seasonal ARIMA Model | The monthly air traffic of a city is a time series with an obvious seasonal pattern, and is closely related to the economic situation and social environment of the city. In Hong Kong, for example, July, August, and October tend to be the peak season of traffic flow, while there is also a relatively fixed off-season. In the case of a stable social environment, a carefully identified and fitted seasonal ARIMA model can predict the traffic flow in the future months well. This work selects the air traffic data, including arrival and departure passengers of Hong Kong, after the financial crisis and before the political storm. A sparse seasonal ARIMA$(0,1,1)\times(4,1,0)_{12}$ is built, which can correctly predict the air traffic from January to July in 2020 within its $95\%$ confidence interval. Furthermore, this work decomposes the time-series and find that important events, like the financial crisis, political storm, and the COVID-19 outbreak, affect the level of air traffic to some extent. For example, the political storm and epidemic prevention and control that happened after 2019 made the air traffic drop significantly. According to my sparse seasonal ARIMA model, the air traffic from February to November in 2020 is only $5\%$ of what it should be without these two events. This is a valuable application of the time-series model in the air traffic loss estimation. | [
"Statistics Archive->stat.AP"
]
| 2021-08-12T15:57:57Z |
1509.02904 | Closing up on Dark Sectors at Colliders: from 14 to 100 TeV | We investigate the reach of the LHC Run 2 and that of a future circular hadron collider with up to 100 TeV centre of mass energy for the exploration of potential Dark Matter sectors. These dark sectors are conveniently and broadly described by simplified models. The simplified models we consider provide microscopic descriptions of interactions between the Standard Model partons and the dark sector particles mediated by the four basic types of messenger fields: scalar, pseudo-scalar, vector or axial-vector. Our analysis extends and updates the previously available results for the LHC at 8 and 14 TeV to 100 TeV for models with all four messenger types. We revisit and improve the analysis at 14 TeV, by studying a variety of analysis techniques, concluding that the most discriminating variables correspond to the missing transverse energy and the azimuthal angle between jets in the final state. Going to 100 TeV, the limits on simplified models of Dark Matter are enhanced significantly, in particular for heavier mediators and dark sector particles, for which the available phase space at the LHC is restricted. The possibility of a 100 TeV collider provides an unprecedented coverage of the dark sector basic parameters and a unique opportunity to pin down the particle nature of Dark Matter and its interactions with the Standard Model. | [
"Physics Archive->hep->hep-ex",
"Physics Archive->hep->hep-ph"
]
| 2015-09-09T19:47:52Z |
1905.10063 | On the GWP of focusing energy-ciritical inhomogeneous NLS | We consider the focussing energy-critical inhomogeneous nonlinear Schr\"odinger equation: $$ iu_t + \Delta u + g|u|^2u = 0, u(0)= \varphi \in \dot{H}^1,\;\; 0 \le g_i \le |x|g \le g_s.$$ On the road map of Kenig-Merle \cite{km} we show the global well-posedness and scattering of radial solutions under energy condition $$E_g(\varphi) < E_g(Q),\;\;\mbox{and}\;\; g_s\|\varphi\|_{\dot{H}^1}^2 < \|Q\|_{\dot{H}^1}^2,$$ where $Q$ is the solution of $\Delta Q + |x|^{-1}Q^3 = 0$, together with scaling condition $|g(x)| + |x||\nabla g(x)| \lesssim |x|^{-1}$, variational condition $g_s(2-g_i) \le 1$, and rigidity condition $-g(x) \le x\cdot \nabla g(x)$. We also provide sharp finite time blowup results for nonradial and radial solutions. For this we utilize the localized virial identity. | [
"Mathematics Archive->math.AP"
]
| 2019-05-24T07:10:59Z |
physics/0607015 | Advances in ion back-flow reduction in cascaded gaseous electron multipliers incorporating R-MHSP elements | A new concept is presented for the reduction of ion back-flow in GEM-based cascaded gaseous electron multipliers, by incorporating Micro-Hole & Strip Plate (MHSP) elements operating in reversed-bias mode (R-MHSP). About an order of magnitude reduction in ion back-flow is achieved by diverting back-drifting ions from their original path. A R-MHSP/2GEM/MHSP cascaded multiplier operated at total gain of ~1.5*10^5 yielded ion back-flow fractions of 0.0015 and 0.0004, at drift fields of 0.5 and 0.1 kV/cm, respectively. A 2R-MHSP/MHSP cascaded multiplier operated at a total gain of ~10^5, yielded an ion back-flow fraction of 0.003. We discuss the concept for trapping back-flowing ions in these cascaded multipliers and the relevance to gaseous photomultiplier and TPC applications; directions for further future developments are outlined. | [
"Physics Archive->physics->physics.ins-det"
]
| 2006-07-03T22:20:04Z |
2108.08262 | SOME/IP Intrusion Detection using Deep Learning-based Sequential Models in Automotive Ethernet Networks | Intrusion Detection Systems are widely used to detect cyberattacks, especially on protocols vulnerable to hacking attacks such as SOME/IP. In this paper, we present a deep learning-based sequential model for offline intrusion detection on SOME/IP application layer protocol. To assess our intrusion detection system, we have generated and labeled a dataset with several classes representing realistic intrusions, and a normal class - a significant contribution due to the absence of such publicly available datasets. Furthermore, we also propose a recurrent neural network (RNN), as an instance of deep learning-based sequential model, that we apply to our generated dataset. The numerical results show that RNN excel at predicting in-vehicle intrusions, with F1 Scores and AUC values greater than 0.8 depending on each intrusion type. | [
"Computer Science Archive->cs.CR",
"Computer Science Archive->cs.LG"
]
| 2021-08-04T09:58:06Z |
1810.05754 | A Word-Complexity Lexicon and A Neural Readability Ranking Model for Lexical Simplification | Current lexical simplification approaches rely heavily on heuristics and corpus level features that do not always align with human judgment. We create a human-rated word-complexity lexicon of 15,000 English words and propose a novel neural readability ranking model with a Gaussian-based feature vectorization layer that utilizes these human ratings to measure the complexity of any given word or phrase. Our model performs better than the state-of-the-art systems for different lexical simplification tasks and evaluation datasets. Additionally, we also produce SimplePPDB++, a lexical resource of over 10 million simplifying paraphrase rules, by applying our model to the Paraphrase Database (PPDB). | [
"Computer Science Archive->cs.CL"
]
| 2018-10-12T23:05:01Z |
1508.06047 | Observation of pentaquark states and perspectives of further studies | In this invited short "news and views", we review very briefly the history of pentaquark studies and the recent observations of the tetraquark and pentaquark states. We also discuss further experimental studies such as at Belle-II. | [
"Physics Archive->hep->hep-ex",
"Physics Archive->hep->hep-ph"
]
| 2015-08-25T07:18:52Z |
astro-ph/0401602 | Revised masses of dust and gas of SLUGS FIR bright galaxies based on a recent CO survey | Recent CO measurements of an essentially complete sub-sample of galaxies from the SCUBA Local Universe Survey (SLUGS) are used to examine their implications for dust and gas masses in this sample. Estimates of dust masses are affected by a contribution to the SCUBA brightness measurements by CO(3-2) emission, and molecular gas masses by the use of a modified value of the CO-to-H_2 conversion factor X. The average dust mass is reduced by 25-38 per cent, which has no bearing on earlier conclusions concering the shapes of the dust mass luminosity function derived from the SLUGS. The value of X found from the CO survey, when applied together with the reduction in dust masses, leads to lower estimates for the mean gas-to-dust mass ratios, where the gas includes both H_2 and HI. For the CO sample, the mean global ratio is reduced from approximately 430 to about 320-360, but is further reduced to values near 50 when applied to the nuclear regions relevant to the CO observations. We discuss these results and suggest that the differences between the nuclear and outer regions may simply reflect differences in metallicity or the existence of considerable amounts of unobserved cold dust in the outer regions of these galaxiies. | [
"Physics Archive->astro-ph"
]
| 2004-01-28T21:59:53Z |
1609.05135 | Virtual Micromagnetics: A Framework for Accessible and Reproducible Micromagnetic Simulation | Computational micromagnetics requires numerical solution of partial differential equations to resolve complex interactions in magnetic nanomaterials. The Virtual Micromagnetics project described here provides virtual machine simulation environments to run open-source micromagnetic simulation packages. These environments allow easy access to simulation packages that are often difficult to compile and install, and enable simulations and their data to be shared and stored in a single virtual hard disk file, which encourages reproducible research. Virtual Micromagnetics can be extended to automate the installation of micromagnetic simulation packages on non-virtual machines, and to support closed-source and new open-source simulation packages, including packages from disciplines other than micromagnetics, encouraging reuse. Virtual Micromagnetics is stored in a public GitHub repository under a three-clause Berkeley Software Distribution (BSD) license. | [
"Computer Science Archive->cs.OH"
]
| 2016-08-11T10:59:40Z |
1211.0987 | Mixing Properties of Commuting Nilmanifold Automorphisms | We study mixing properties of commutative groups of automorphisms acting on compact nilmanifolds. Assuming that every nontrivial element acts ergodically, we prove that such actions are mixing of all orders. We further show exponential 2-mixing and 3-mixing. As an application we prove smooth cocycle rigidity for higher-rank abelian groups of nilmanifold automorphisms. | [
"Mathematics Archive->math.DS"
]
| 2012-11-05T19:59:55Z |
quant-ph/9507001 | Newtonian Quantum Gravity | Puts forward a complete scenario for interpreting nonlinear field theories highlighting the role played by gravitational self--energy in enabling a consistent revival of the Schroedinger approach to unifying micro and macro physics. | [
"Physics Archive->quant-ph"
]
| 1995-07-04T04:18:29Z |
2308.02070 | Nonlinearly Elastic Maps: Energy Minimizing Configurations of Membranes on Prescribed Surfaces | We propose a model for nonlinearly elastic membranes and consider deformations confined to a regular frictionless surface in $\mathbb{R}^3$. This is a physically correct model of the sometimes crudely stated motivation for harmonic maps between manifolds. The membrane energy function is convex in the strain pair comprising the deformation gradient and the local area ratio. If the target surface is a plane, the problem reduces to 2-dimensional, polyconvex nonlinear elasticity. On the other hand, the energy density is not rank-one convex for unconstrained deformations into $\mathbb{R}^3$. We show that the problem admits an energy-minimizing configuration when constrained to lie on the given surface. For a class of Dirichlet-placement problems, we demonstrate that the minimizing deformation is a homeomorphism onto its image and establish the weak Eulerian form of the equilibrium equations. | [
"Mathematics Archive->math.AP"
]
| 2023-08-03T22:53:26Z |
astro-ph/9801124 | High Metallicity Mg II Absorbers in the z < 1 Lyman alpha Forest of PKS 0454+039: Giant LSB Galaxies? | We report the discovery of two iron-group enhanced high-metallicity Mg II absorbers in a search through 28 Lyman Alpha forest clouds along the PKS 0454+039 sight line. Based upon our survey and the measured redshift number densities of W_r(MgII) <= 0.3 A absorbers and Lyman Alpha absorbers at z ~ 1, we suggest that roughly 5% of Lyman Alpha absorbers at z < 1 will exhibit "weak" Mg II absorption to a 5-sigma W_r(2796) detection limit of 0.02 A. The two discovered absorbers, at redshifts z = 0.6248 and z = 0.9315, have W_r(Lya) = 0.33 and 0.15 A, respectively. Based upon photoionization modeling, the H I column densities are inferred to be in the range 15.8 <= log N(HI) <= 16.8 cm^-2. For the z = 0.6428 absorber, if the abundance pattern is solar, then the cloud has [Fe/H] > -1; if its gas-phase abundance follows that of depleted clouds in our Galaxy, then [Fe/H] > 0 is inferred. For the z = 0.9315 absorber, the metallicity is [Fe/H] > 0, whether the abundance pattern is solar or suffers depletion. Imaging and spectroscopic studies of the PKS 0454+039 field reveal no candidate luminous objects at these redshifts. We discuss the possibility that these Mg II absorbers may arise in the class of "giant" low surface brightness galaxies, which have [Fe/H] >= -1, and even [Fe/H] >= 0, in their extended disks. We tentatively suggest that a substantial fraction of these "weak" Mg II absorbers may select low surface brightness galaxies out to z ~ 1. | [
"Physics Archive->astro-ph"
]
| 1998-01-14T02:38:30Z |
1507.02513 | A Review of Methods for the Analysis of the Expected Value of Information | Over recent years Value of Information analysis has become more widespread in health-economic evaluations, specifically as a tool to perform Probabilistic Sensitivity Analysis. This is largely due to methodological advancements allowing for the fast computation of a typical summary known as the Expected Value of Partial Perfect Information (EVPPI). A recent review discussed some estimations method for calculating the EVPPI but as the research has been active over the intervening years this review does not discuss some key estimation methods. Therefore, this paper presents a comprehensive review of these new methods. We begin by providing the technical details of these computation methods. We then present a case study in order to compare the estimation performance of these new methods. We conclude that the most recent development based on non-parametric regression offers the best method for calculating the EVPPI efficiently. This means that the EVPPI can now be used practically in health economic evaluations, especially as all the methods are developed in parallel with R | [
"Statistics Archive->stat.AP"
]
| 2015-07-09T14:10:41Z |
1112.1380 | Light-matter interaction in a microcavity-controlled graphene transistor | Graphene has extraordinary electronic and optical properties and holds great promise for applications in photonics and optoelectronics. Demonstrations including high-speed photodetectors, optical modulators, plasmonic devices, and ultrafast lasers have now been reported. More advanced device concepts would involve photonic elements such as cavities to control light-matter interaction in graphene. Here we report the first monolithic integration of a graphene transistor and a planar, optical microcavity. We find that the microcavity-induced optical confinement controls the efficiency and spectral selection of photocurrent generation in the integrated graphene device. A twenty-fold enhancement of photocurrent is demonstrated. The optical cavity also determines the spectral properties of the electrically excited thermal radiation of graphene. Most interestingly, we find that the cavity confinement modifies the electrical transport characteristics of the integrated graphene transistor. Our experimental approach opens up a route towards cavity-quantum electrodynamics on the nanometre scale with graphene as a current-carrying intra-cavity medium of atomic thickness. | [
"Physics Archive->cond-mat->cond-mat.mes-hall"
]
| 2011-12-06T19:27:55Z |
0810.4393 | Gravitational Waves in Relativistic Theory of Gravitation | It is shown that, in the framework of Relativistic Theory of Gravitation with massive graviton, gravitational waves, due to the causality condition, do not bear negative energy flows. | [
"Physics Archive->gr-qc"
]
| 2008-10-24T07:41:31Z |
1611.10296 | Scheduling of EV Battery Swapping, II: Distributed Solutions | In Part I of this paper we formulate an optimal scheduling problem for battery swapping that assigns to each electric vehicle (EV) a best station to swap its depleted battery based on its current location and state of charge. The schedule aims to minimize a weighted sum of total travel distance and generation cost over both station assignments and power flow variables, subject to EV range constraints, grid operational constraints and AC power flow equations. We propose there a centralized solution based on the second-order cone programming (SOCP) relaxation of optimal power flow (OPF) and generalized Benders decomposition that is suitable when global information is available. In this paper we propose two distributed solutions based on the alternating direction method of multipliers (ADMM) and dual decomposition respectively that are suitable for cases where the distribution grid, battery stations and EVs are managed by separate entities. Our algorithms allow these entities to make individual decisions but coordinate through privacy-preserving information exchanges to jointly solve an approximate version of the joint battery swapping scheduling and OPF problem. We evaluate our algorithms through simulations. | [
"Mathematics Archive->math.OC"
]
| 2016-11-30T18:10:39Z |
1108.2053 | Screening in strongly coupled N=2* supersymmetric Yang-Mills plasma | Using gauge-gravity duality, we extend thermodynamic studies and present results for thermal screening masses in strongly coupled N=2* supersymmetric Yang-Mills theory. This non-conformal theory is a mass deformation of maximally supersymmetric N=4 gauge theory. Results are obtained for the entropy density, pressure, specific heat, equation of state, and screening masses, down to previously unexplored low temperatures. The temperature dependence of screening masses in various symmetry channels, which characterize the longest length scales over which thermal fluctuations in the non-Abelian plasma are correlated, is examined and found to be asymptotically linear in the low temperature regime. | [
"Physics Archive->hep->hep-th"
]
| 2011-08-09T21:14:08Z |
2109.07936 | Noise-driven bifurcations in a neural field system modelling networks of grid cells | The activity generated by an ensemble of neurons is affected by various noise sources. It is a well-recognised challenge to understand the effects of noise on the stability of such networks. We demonstrate that the patterns of activity generated by networks of grid cells emerge from the instability of homogeneous activity for small levels of noise. This is carried out by analysing the robustness of network activity patterns with respect to noise in an upscaled noisy grid cell model in the form of a system of partial differential equations. Inhomogeneous network patterns are numerically understood as branches bifurcating from unstable homogeneous states for small noise levels. We show that there is a phase transition occurring as the level of noise decreases. Our numerical study also indicates the presence of hysteresis phenomena close to the precise critical noise value. | [
"Mathematics Archive->math.AP"
]
| 2021-09-16T12:35:27Z |
2107.02829 | Search-based Path Planning for a High Dimensional Manipulator in Cluttered Environments Using Optimization-based Primitives | In this work we tackle the path planning problem for a 21-dimensional snake robot-like manipulator, navigating a cluttered gas turbine for the purposes of inspection. Heuristic search based approaches are effective planning strategies for common manipulation domains. However, their performance on high dimensional systems is heavily reliant on the effectiveness of the action space and the heuristics chosen. The complex nature of our system, reachability constraints, and highly cluttered turbine environment renders naive choices of action spaces and heuristics ineffective. To this extent we have developed i) a methodology for dynamically generating actions based on online optimization that help the robot navigate narrow spaces, ii) a technique for lazily generating these computationally expensive optimization actions to effectively utilize resources, and iii) heuristics that reason about the homotopy classes induced by the blades of the turbine in the robot workspace and a Multi-Heuristic framework which guides the search along the relevant classes. The impact of our contributions is presented through an experimental study in simulation, where the 21 DOF manipulator navigates towards regions of inspection within a turbine. | [
"Computer Science Archive->cs.RO"
]
| 2021-07-06T18:21:21Z |
1910.12717 | Sampling of Bayesian posteriors with a non-Gaussian probabilistic learning on manifolds from a small dataset | This paper tackles the challenge presented by small-data to the task of Bayesian inference. A novel methodology, based on manifold learning and manifold sampling, is proposed for solving this computational statistics problem under the following assumptions: 1) neither the prior model nor the likelihood function are Gaussian and neither can be approximated by a Gaussian measure; 2) the number of functional input (system parameters) and functional output (quantity of interest) can be large; 3) the number of available realizations of the prior model is small, leading to the small-data challenge typically associated with expensive numerical simulations; the number of experimental realizations is also small; 4) the number of the posterior realizations required for decision is much larger than the available initial dataset. The method and its mathematical aspects are detailed. Three applications are presented for validation: The first two involve mathematical constructions aimed to develop intuition around the method and to explore its performance. The third example aims to demonstrate the operational value of the method using a more complex application related to the statistical inverse identification of the non-Gaussian matrix-valued random elasticity field of a damaged biological tissue (osteoporosis in a cortical bone) using ultrasonic waves. | [
"Computer Science Archive->cs.LG",
"Statistics Archive->stat.ML"
]
| 2019-10-28T14:37:08Z |
1612.09465 | Adaptive Lambda Least-Squares Temporal Difference Learning | Temporal Difference learning or TD($\lambda$) is a fundamental algorithm in the field of reinforcement learning. However, setting TD's $\lambda$ parameter, which controls the timescale of TD updates, is generally left up to the practitioner. We formalize the $\lambda$ selection problem as a bias-variance trade-off where the solution is the value of $\lambda$ that leads to the smallest Mean Squared Value Error (MSVE). To solve this trade-off we suggest applying Leave-One-Trajectory-Out Cross-Validation (LOTO-CV) to search the space of $\lambda$ values. Unfortunately, this approach is too computationally expensive for most practical applications. For Least Squares TD (LSTD) we show that LOTO-CV can be implemented efficiently to automatically tune $\lambda$ and apply function optimization methods to efficiently search the space of $\lambda$ values. The resulting algorithm, ALLSTD, is parameter free and our experiments demonstrate that ALLSTD is significantly computationally faster than the na\"{i}ve LOTO-CV implementation while achieving similar performance. | [
"Computer Science Archive->cs.AI",
"Computer Science Archive->cs.LG",
"Statistics Archive->stat.ML"
]
| 2016-12-30T11:51:14Z |
1203.5918 | Perturbative QCD for B_s \to a_1(1260)(b_1(1235))P(V) Decays | Within the framework of perturbative QCD approach, we study the charmless two-body decays $B_s \to a_1(1260)(b_1(1235))P(V)$ ($P, V$ represent the light pseudo-scalar and vector mesons, respectively.). Using the decays constants and the light-cone distribution amplitudes for these mesons derived from the QCD sum rule method, we find the following results: (a) The decays $\bar B^0_s\to a^{-}_1K^{+}(K^{*+})$ have the contributions from the factorization emission diagrams with a large Wilson coefficient $C_2+C_1/3$ (order of 1), so they have the largest branching ratios and arrive at $10^{-5}$ order. While for the decays $\bar B^0_s\to a^{0}_1 K^{0}(K^{*0})$, the Wilson coefficient is $C_1+C_2/3$ in tree level and color suppressed, so their branching ratios are small and fall in the order of $10^{-7}\sim10^{-8}$. For the decays $\bar B^0_s\to b_1K(K^*)$, all of their branching ratios are of order few times $10^{-6}$. (b) For the pure annihilation type decays $\bar B^0_s\to a_1(b_1)\rho$ except the decays $\bar B^0_s\to a_1\pi$ having large branching ratios of order few times $10^{-6}$, the most other decays have the branching ratios of $10^{-7}$ order. The branching ratios of the decays $\bar B^0_s\to a^0_1(b^0_1)\omega$ are the smallest and fall in the order of $10^{-8}\sim10^{-9}$. (c)The branching ratios and the direct CP-asymmetries of decays $\bar B^0_s\to a^0_1(b_1^0)\eta^{(\prime)}$ are very sensitive to take different Gegenbauer moments for $\eta^{(\prime)}$. (d) Except for the decays $\bar B^0_s\to a^{0}_1 K^{*0}, a^{0}_1\omega, b^{0}_1\omega$, the longitudinal polarization fractions of other $\bar B^0_s\to a_1(b_1)V$ decays are very large and more than 90%. (e) Compared with decays $\bar B^0_s\to a_1(b_1)P$, most of $\bar B^0_s\to a_1(b_1)V$ decays have smaller direct CP asymmetries. | [
"Physics Archive->hep->hep-ph"
]
| 2012-03-27T10:24:19Z |
cond-mat/0603097 | Lower Pseudogap Phase: A Spin/Vortex Liquid State | The pseudogap phase is considered as a new state of matter in the phase string model of the doped Mott insulator, which is composed of two distinct regimes known as upper and lower pseudogap phases, respectively. The former corresponds to the formation of spin singlet pairing and the latter is characterized by the formation of the Cooper pair amplitude and described by a generalized Gingzburg-Landau theory. Elementary excitation in this phase is a charge-neutral object carrying spin-1/2 and locking with a supercurrent vortex, known as spinon-vortex composite. Here thermally excited spinon-vortices destroy the phase coherence and are responsible for nontrivial Nernst effect and diamagnetism. The transport entropy and core energy associated with a spinon-vortex are determined by the spin degrees of freedom. Such a spontaneous vortex liquid phase can be also considered as a spin liquid with a finite correlation length and gapped S=1/2 excitations, where a resonancelike non-propagating spin mode emerges at the antiferromagnetic wavevector with a doping-dependent characteristic energy. A quantitative phase diagram in the parameter space of doping, temperature, and magnetic field is determined. Comparisons with experiments are also made. | [
"Physics Archive->cond-mat->cond-mat.str-el",
"Physics Archive->cond-mat->cond-mat.supr-con"
]
| 2006-03-05T02:00:30Z |
1602.07812 | Symmetry-breaking bifurcation for the one-dimensional Liouville type equation | The two-point boundary value problem for the one-dimensional Liouville type equation is considered. In this paper, a symmetry-breaking result is obtained by using the Morse index. | [
"Mathematics Archive->math.AP"
]
| 2016-02-25T06:07:03Z |
0705.2203 | An absolute quantum energy inequality for the Dirac field in curved spacetime | Quantum Weak Energy Inequalities (QWEIs) are results which limit the extent to which the smeared renormalised energy density of a quantum field can be negative. On globally hyperbolic spacetimes the massive quantum Dirac field is known to obey a QWEI in terms of a reference state chosen arbitrarily from the class of Hadamard states; however, there exist spacetimes of interest on which state-dependent bounds cannot be evaluated. In this paper we prove the first QWEI for the massive quantum Dirac field on four dimensional globally hyperbolic spacetime in which the bound depends only on the local geometry; such a QWEI is known as an absolute QWEI. | [
"Physics Archive->gr-qc"
]
| 2007-05-15T18:00:47Z |
1805.06522 | Semantic Relatedness for All (Languages): A Comparative Analysis of Multilingual Semantic Relatedness Using Machine Translation | This paper provides a comparative analysis of the performance of four state-of-the-art distributional semantic models (DSMs) over 11 languages, contrasting the native language-specific models with the use of machine translation over English-based DSMs. The experimental results show that there is a significant improvement (average of 16.7% for the Spearman correlation) by using state-of-the-art machine translation approaches. The results also show that the benefit of using the most informative corpus outweighs the possible errors introduced by the machine translation. For all languages, the combination of machine translation over the Word2Vec English distributional model provided the best results consistently (average Spearman correlation of 0.68). | [
"Computer Science Archive->cs.CL"
]
| 2018-05-16T20:43:45Z |
1901.04387 | (Un)distorted stabilisers in the handlebody group | We study geometric properties of stabilisers in the handlebody group. We find that stabilisers of meridians are undistorted, while stabilisers of primitive curves or annuli are exponentially distorted for large enough genus. | [
"Mathematics Archive->math.GR",
"Mathematics Archive->math.GT"
]
| 2019-01-14T16:36:57Z |
1801.06678 | $\mathcal {PT}$-symmetric circuit-QED | The Hermiticity axiom of quantum mechanics guarantees that the energy spectrum is real and the time evolution is unitary (probability-preserving). Nevertheless, non-Hermitian but $\mathcal{PT}$-symmetric Hamiltonians may also have real eigenvalues. Systems described by such effective $\mathcal {PT}$-symmetric Hamiltonians have been realized in experiments using coupled systems with balanced loss (dissipation) and gain (amplification), and their corresponding classical dynamics has been studied. A $\mathcal {PT}$-symmetric system emerging from a quantum dynamics is highly desirable, in order to understand what $\mathcal {PT}$-symmetry and the powerful mathematical and physical concepts around it will bring to the next generation of quantum technologies. Here, we address this need by proposing and studying a circuit-QED architecture that consists of two coupled resonators and two qubits (each coupled to one resonator). By means of external driving fields on the qubits, we are able to tune gain and losses in the resonators. Starting with the quantum dynamics of this system, we show the emergence of the $\mathcal {PT}$-symmetry via the selection of both driving amplitudes and frequencies. We engineer the system such that a non-number conserving dipole-dipole interaction emerges, introducing an instability at large coupling strengths. The $\mathcal {PT}$-symmetry and its breaking, as well as the predicted instability in this circuit-QED system can be observed in a transmission experiment. | [
"Physics Archive->quant-ph"
]
| 2018-01-20T13:59:54Z |
2308.07527 | FeatGeNN: Improving Model Performance for Tabular Data with Correlation-based Feature Extraction | Automated Feature Engineering (AutoFE) has become an important task for any machine learning project, as it can help improve model performance and gain more information for statistical analysis. However, most current approaches for AutoFE rely on manual feature creation or use methods that can generate a large number of features, which can be computationally intensive and lead to overfitting. To address these challenges, we propose a novel convolutional method called FeatGeNN that extracts and creates new features using correlation as a pooling function. Unlike traditional pooling functions like max-pooling, correlation-based pooling considers the linear relationship between the features in the data matrix, making it more suitable for tabular data. We evaluate our method on various benchmark datasets and demonstrate that FeatGeNN outperforms existing AutoFE approaches regarding model performance. Our results suggest that correlation-based pooling can be a promising alternative to max-pooling for AutoFE in tabular data applications. | [
"Computer Science Archive->cs.LG",
"Computer Science Archive->cs.NE"
]
| 2023-08-15T01:48:11Z |
1910.07103 | Existence of a $T$-periodic solution for the monodomain model corresponding to an isolated ventricle due to ionic-diffusive relations | In this paper, we find relations between the ionic parameters and the diffusion parameters which are sufficient to ensure the existence of a periodic solution for a well-known monodomain model in a weak sense. We make use of the method of approximation of Faedo-Galerkin to prove the existence of weak periodic solutions of the monodomain model for the electrical activity of the heart assuming that it is periodically activated in its boundaries. Actually, this periodic solution has the same period of activation. Finally, we reflect on how these ionic-diffusive relations are useful to explain the pathophysiology of some rhythm disorders. | [
"Mathematics Archive->math.AP"
]
| 2019-10-15T23:26:38Z |
2011.09272 | Combining Prosodic, Voice Quality and Lexical Features to Automatically Detect Alzheimer's Disease | Alzheimer's Disease (AD) is nowadays the most common form of dementia, and its automatic detection can help to identify symptoms at early stages, so that preventive actions can be carried out. Moreover, non-intrusive techniques based on spoken data are crucial for the development of AD automatic detection systems. In this light, this paper is presented as a contribution to the ADReSS Challenge, aiming at improving AD automatic detection from spontaneous speech. To this end, recordings from 108 participants, which are age-, gender-, and AD condition-balanced, have been used as training set to perform two different tasks: classification into AD/non-AD conditions, and regression over the Mini-Mental State Examination (MMSE) scores. Both tasks have been performed extracting 28 features from speech -- based on prosody and voice quality -- and 51 features from the transcriptions -- based on lexical and turn-taking information. Our results achieved up to 87.5 % of classification accuracy using a Random Forest classifier, and 4.54 of RMSE using a linear regression with stochastic gradient descent over the provided test set. This shows promising results in the automatic detection of Alzheimer's Disease through speech and lexical features. | [
"Computer Science Archive->cs.CL",
"Computer Science Archive->cs.SD",
"Electrical Engineering and Systems Science Archive->eess.AS"
]
| 2020-11-18T13:37:27Z |
2110.00376 | An absolute version of the Gromov-Lawson relative index theorem | A Dirac operator on a complete manifold is Fredholm if it is invertible outside a compact set. Assuming a compact group to act on all relevant structure, and the manifold to have a warped product structure outside such a compact set, we express the equivariant index of such a Dirac operator as an Atiyah-Segal-Singer type contribution from inside this compact set, and a contribution from outside this set. Consequences include equivariant versions of the relative index theorem of Gromov and Lawson, in the case of manifolds with warped product structures at infinity, and the Atiyah-Patodi-Singer index theorem. | [
"Mathematics Archive->math.DG"
]
| 2021-10-01T13:10:33Z |
1606.05174 | Deep Reinforcement Learning Discovers Internal Models | Deep Reinforcement Learning (DRL) is a trending field of research, showing great promise in challenging problems such as playing Atari, solving Go and controlling robots. While DRL agents perform well in practice we are still lacking the tools to analayze their performance. In this work we present the Semi-Aggregated MDP (SAMDP) model. A model best suited to describe policies exhibiting both spatial and temporal hierarchies. We describe its advantages for analyzing trained policies over other modeling approaches, and show that under the right state representation, like that of DQN agents, SAMDP can help to identify skills. We detail the automatic process of creating it from recorded trajectories, up to presenting it on t-SNE maps. We explain how to evaluate its fitness and show surprising results indicating high compatibility with the policy at hand. We conclude by showing how using the SAMDP model, an extra performance gain can be squeezed from the agent. | [
"Computer Science Archive->cs.AI"
]
| 2016-06-16T13:09:16Z |
1510.01513 | On the Riemann-Hilbert problem for analytic functions in circular domains | It is proved the existence of single-valued analytic solutions in the unit disk and multivalent analytic solutions in domains bounded by a finite collection of circles for the Riemann-Hilbert problem with coefficients of sigma-finite variation and with boundary data that are measurable with respect to logarithmic capacity. It is shown that these spaces of solutions have the infinite dimension. | [
"Mathematics Archive->math.CV"
]
| 2015-10-06T10:26:51Z |
2310.12772 | On Some Intersection Properties of Finite Groups | In this article, we introduce the study of a class of finite groups $G$ which admits a subgroup which intersects all non-trivial subgroups of $G$. We also explore a subclass of it consisting of all groups $G$ in which the prime order elements commute. In particular, we discuss the relationship between these class of groups with other known classes of finite groups, like simple groups, perfect groups etc. Moreover, we also prove some results on the possible orders of such groups. Finally, we conclude with some open issues. | [
"Mathematics Archive->math.GR"
]
| 2023-10-19T14:20:13Z |
1610.07828 | On a hyperbolic system arising in liquid crystals modeling | We consider a model of liquid crystals, based on a nonlinear hyperbolic system of differential equations, that represents an inviscid version of the model proposed by Qian and Sheng. A new concept of dissipative solution is proposed, for which a global-in-time existence theorem is shown. The dissipative solutions enjoy the following properties: (i) they exist globally in time for any finite energy initial data; (ii) dissipative solutions enjoying certain smoothness are classical solutions; (iii) a dissipative solution coincides with a strong solution originating from the same initial data as long as the latter exists. | [
"Mathematics Archive->math.AP"
]
| 2016-10-25T11:15:11Z |
1905.09750 | Approximation schemes for the generalized extensible bin packing problem | We present a new generalization of the extensible bin packing with unequal bin sizes problem. In our generalization the cost of exceeding the bin size depends on the index of the bin and not only on the amount in which the size of the bin is exceeded. This generalization does not satisfy the assumptions on the cost function that were used to present the existing polynomial time approximation scheme (PTAS) for the extensible bin packing with unequal bin sizes problem. In this work, we show the existence of an efficient PTAS (EPTAS) for this new generalization and thus in particular we improve the earlier PTAS for the extensible bin packing with unequal bin sizes problem into an EPTAS. Our new scheme is based on using the shifting technique followed by a solution of polynomial number of $n$-fold programming instances. In addition, we present an asymptotic fully polynomial time approximation scheme (AFPTAS) for the related bin packing type variant of the problem. | [
"Computer Science Archive->cs.DS"
]
| 2019-05-23T16:11:45Z |
quant-ph/0703255 | Quantum Communication | Quantum communication, and indeed quantum information in general, has changed the way we think about quantum physics. In 1984 and 1991, the first protocol for quantum cryptography and the first application of quantum non-locality, respectively, attracted a diverse field of researchers in theoretical and experimental physics, mathematics and computer science. Since then we have seen a fundamental shift in how we understand information when it is encoded in quantum systems. We review the current state of research and future directions in this new field of science with special emphasis on quantum key distribution and quantum networks. | [
"Physics Archive->quant-ph"
]
| 2007-03-27T20:10:10Z |
math/0001066 | On some Moment Maps and Induced Hopf Bundles in the Quaternionic Projective Space | We describe a diagram containing the zero sets of the moment maps associated to the diagonal U(1) and Sp(1) actions on the quaternionic projective space HP^n. These sets are related both to focal sets of submanifolds and to Sasakian-Einstein structures on induced Hopf bundles. As an application, we construct a complex structure on the Stiefel manifolds V_2 (C^{n+1}) and V_4 (R^{n+1}), the one on the former manifold not being compatible with its known hypercomplex structure. | [
"Mathematics Archive->math.DG"
]
| 2000-01-12T13:07:12Z |
0810.5141 | Challenges in Hadronic Form Factor Calculations | There is an extensive history of form factor calculations on the lattice, primarily with ground states for both initial and final states. However, there have never been any radially excited transition form factor calculations. Furthermore, the lattice faces difficulty in extracting signal from noise at large transfer momenta ($Q^2$). These measurements could give important theoretical input to experiments, such as those of JLab's 12 GeV program and studies of deformation of the nucleon. In this work, I will present a simple technique to resolve both of these difficulties and present results from anisotropic configurations showing improved signals for excited-state quantities. It should also be possible to apply this technique to isotropic lattices for calculating large-$Q^2$ form factors. | [
"Physics Archive->hep->hep-lat"
]
| 2008-10-28T20:54:23Z |
1910.07362 | Compact and Limited Operators | Let $T:Y\to X$ be a bounded linear operator between two normed spaces. We characterize compactness of $T$ in terms of differentiability of the Lipschitz functions defined on $X$ with values in another normed space $Z$. Furthermore, using a similar technique we can also characterize finite rank operators in terms of differentiability of a wider class of functions but still with Lipschitz flavour. As an application we obtain a Banach-Stone-like theorem. On the other hand, we give an extension of a result of Bourgain and Diestel related to limited operators and cosingularity. | [
"Mathematics Archive->math.FA"
]
| 2019-10-16T14:14:11Z |
1707.03505 | Proximally Guided Stochastic Subgradient Method for Nonsmooth, Nonconvex Problems | In this paper, we introduce a stochastic projected subgradient method for weakly convex (i.e., uniformly prox-regular) nonsmooth, nonconvex functions---a wide class of functions which includes the additive and convex composite classes. At a high-level, the method is an inexact proximal point iteration in which the strongly convex proximal subproblems are quickly solved with a specialized stochastic projected subgradient method. The primary contribution of this paper is a simple proof that the proposed algorithm converges at the same rate as the stochastic gradient method for smooth nonconvex problems. This result appears to be the first convergence rate analysis of a stochastic (or even deterministic) subgradient method for the class of weakly convex functions. | [
"Computer Science Archive->cs.LG",
"Mathematics Archive->math.OC"
]
| 2017-07-12T00:35:43Z |
1407.0187 | Fourier theory of linear gain media | The analysis of wave propagation in linear, passive media is usually done by considering a single real frequency (the monochromatic limit) and also often a single plane wave component (plane wave limit), separately. For gain media, we demonstrate that these two limits generally do not commute; for example, one order may lead to a diverging field, while the other order leads to a finite field. Moreover, the plane wave limit may be dependent on whether it is realized with a rect function excitation or gaussian excitation of infinite widths. We consider wave propagation in gain media by a Fourier--Laplace integral in time and space, and demonstrate how the correct monochromatic limit or plane wave limit can be taken, by deforming the integration surface in complex frequency--complex wavenumber space. We also give the most general criterion for absolute instabilities. The general theory is applied in several cases, and is used to predict media with novel properties. In particular, we show the existence of isotropic media which in principle exhibit simultaneous refraction, meaning that they refract positively and negatively at the same time. | [
"Physics Archive->physics->physics.optics"
]
| 2014-07-01T11:04:05Z |
astro-ph/0701143 | High-redshift obscured quasars | Using mid-infrared and radio criteria, we select a sample of candidate z~2 obscured quasars. Optical spectroscopy confirms about half of these as type-2 quasars, and modelling the population suggests 50-80% of the quasars are obscured. We find some flat radio spectrum type-2 quasars, and tentative evidence for obscuration unrelated to the torus. Using a similar sample, we also find evidence for a significant fraction of Compton-thick quasars. | [
"Physics Archive->astro-ph"
]
| 2007-01-05T16:18:29Z |
1910.04190 | Bosonization of the Thirring Model in 2+1 Dimensions | In this work we provide a bosonized version of the Thirring model in 2+1 dimensions in the case of single fermion species, where we do not have the benefit of large N expansion. In this situation there are very few analytical methods to extract nonperturbative information. Meanwhile, nontrivial behavior is expected to take place precisely in this regime. To establish the bosonization of the Thirring model, we consider a deformation of a basic fermion-boson duality relation in 2+1 dimensions. The bosonized model interpolates between the ultraviolet and infrared regimes, passing several consistency checks and recovering the usual bosonization relation of the web of dualities in the infrared limit. In addition the duality predicts the existence of a nontrivial ultraviolet fixed point in the Thirring model. | [
"Physics Archive->cond-mat->cond-mat.str-el",
"Physics Archive->hep->hep-th"
]
| 2019-10-09T18:16:56Z |
1706.00810 | Singular perturbation for abstract elliptic equations and application | Boundary value problem for complete second order elliptic equation is considered in Banach space. The equation and boundary conditions involve a small and spectral parameter. The uniform L_{p}-regularity properties with respect to space variable and parameters are established. Here, the explicit formula for the solution is given and behavior of solution is derived when the small parameter approaches zero. It used to obtain singular perturbation result for abstract elliptic equation | [
"Mathematics Archive->math.AP",
"Mathematics Archive->math.FA"
]
| 2017-05-23T07:04:22Z |
1809.02818 | Nullstellens\"atze and Applications | In this expository paper, we present simple proofs of the Classical, Real, Projective and Combinatorial Nullstellens\"atze. Several applications are also presented such as a classical theorem of Stickelberger for solutions of polynomial equations in terms of eigenvalues of commuting operators, construction of a principal ideal domain which is not Euclidean, Hilbert's $17^{th}$ problem, the Borsuk-Ulam theorem in topology and solutions of the conjectures of Dyson, Erd\"{o}s and Heilbronn. | [
"Mathematics Archive->math.AC"
]
| 2018-09-08T15:05:51Z |
0906.1902 | Inflation and Reheating in Induced Gravity | Inflation is studied in the context of induced gravity (IG) $\gamma \sigma^2 R$, where $R$ is the Ricci scalar, $\sigma$ a scalar field and $\gamma$ a dimensionless constant. We study in detail cosmological perturbations in IG and examine both a Landau-Ginzburg (LG) and a Coleman-Weinberg (CW) potential toy models for small field and large field (chaotic) inflation and find that small field inflationary models in IG are constrained to $\gamma \lesssim 3 \times 10^{-3}$ by WMAP 5 yrs data. Finally we describe the regime of coherent oscillations in induced gravity by an analytic approximation, showing how the homogeneous inflaton can decay in its short-scale fluctuations when it oscillates around a non-zero value $\sigma_0$. | [
"Physics Archive->astro-ph->astro-ph.CO",
"Physics Archive->gr-qc",
"Physics Archive->hep->hep-th"
]
| 2009-06-10T10:01:20Z |
2108.08922 | Controlled GAN-Based Creature Synthesis via a Challenging Game Art Dataset -- Addressing the Noise-Latent Trade-Off | The state-of-the-art StyleGAN2 network supports powerful methods to create and edit art, including generating random images, finding images "like" some query, and modifying content or style. Further, recent advancements enable training with small datasets. We apply these methods to synthesize card art, by training on a novel Yu-Gi-Oh dataset. While noise inputs to StyleGAN2 are essential for good synthesis, we find that coarse-scale noise interferes with latent variables on this dataset because both control long-scale image effects. We observe over-aggressive variation in art with changes in noise and weak content control via latent variable edits. Here, we demonstrate that training a modified StyleGAN2, where coarse-scale noise is suppressed, removes these unwanted effects. We obtain a superior FID; changes in noise result in local exploration of style; and identity control is markedly improved. These results and analysis lead towards a GAN-assisted art synthesis tool for digital artists of all skill levels, which can be used in film, games, or any creative industry for artistic ideation. | [
"Computer Science Archive->cs.CV"
]
| 2021-08-19T21:31:20Z |
math-ph/0404007 | Pohlmeyer invariants are expressible in terms of DDF invariants | It is shown that the Pohlmeyer invariants of the classical bosonic string are a proper subset of the classical DDF invariants. This makes the quantization of the Pohlmeyer invariants particularly transparent and allows to generalize them to the superstring. | [
"Mathematics Archive->math.MP",
"Physics Archive->math-ph"
]
| 2004-04-02T13:55:49Z |
1908.06490 | Geometry and integrability in $\mathcal{N}=8$ supersymmetric mechanics | We construct the $\mathcal{N}=8$ supersymmetric mechanics with potential term whose configuration space is the special K\"ahler manifold of rigid type and show that it can be viewed as the K\"ahler counterpart of $\mathcal{N}=4$ mechanics related to "curved WDVV equations". Then, we consider the special case of the supersymmetric mechanics with the non-zero potential term defined on the family of $U(1)$-invariant one-(complex)dimensional special K\"ahler metrics. The bosonic parts of these systems include superintegrable deformations of perturbed two-dimensional oscillator and Coulomb systems. | [
"Mathematics Archive->math.MP",
"Physics Archive->hep->hep-th",
"Physics Archive->math-ph"
]
| 2019-08-18T18:02:23Z |
1501.05319 | Maximum nonlocality and minimum uncertainty using magic states | We prove that magic states from the Clifford hierarchy give optimal solutions for tasks involving nonlocality and entropic uncertainty with respect to Pauli measurements. For both the nonlocality and uncertainty tasks, stabilizer states are the worst possible pure states so our solutions have an operational interpretation as being highly non-stabilizer. The optimal strategy for a qudit version of the Clauser-Horne-Shimony-Holt (CHSH) game in prime dimensions is achieved by measuring maximally entangled states that are isomorphic to single-qudit magic states. These magic states have an appealingly simple form and our proof shows that they are "balanced" with respect to all but one of the mutually unbiased stabilizer bases. Of all equatorial qudit states, magic states minimize the average entropic uncertainties for collision entropy and also, for small prime dimensions, min-entropy -- a fact that may have implications for cryptography. | [
"Physics Archive->quant-ph"
]
| 2015-01-21T21:00:51Z |
2110.04004 | Trident Pyramid Networks: The importance of processing at the feature pyramid level for better object detection | Feature pyramids have become ubiquitous in multi-scale computer vision tasks such as object detection. Given their importance, a computer vision network can be divided into three parts: a backbone (generating a feature pyramid), a neck (refining the feature pyramid) and a head (generating the final output). Many existing networks operating on feature pyramids, named necks, are shallow and mostly focus on communication-based processing in the form of top-down and bottom-up operations. We present a new neck architecture called Trident Pyramid Network (TPN), that allows for a deeper design and for a better balance between communication-based processing and self-processing. We show consistent improvements when using our TPN neck on the COCO object detection benchmark, outperforming the popular BiFPN baseline by 0.5 AP, both when using the ResNet-50 and the ResNeXt-101-DCN backbone. Additionally, we empirically show that it is more beneficial to put additional computation into the TPN neck, rather than into the backbone, by outperforming a ResNet-101+FPN baseline with our ResNet-50+TPN network by 1.7 AP, while operating under similar computation budgets. This emphasizes the importance of performing computation at the feature pyramid level in modern-day object detection systems. Code is available at https://github.com/CedricPicron/TPN . | [
"Computer Science Archive->cs.CV"
]
| 2021-10-08T09:59:59Z |
hep-th/9211042 | Self--Dual Supergravity and Supersymmetric Yang--Mills Coupled to Green--Schwarz Superstring | We present the {\it canonical} set of superspace constraints for self-dual supergravity, a ``self-dual'' tensor multiplet and a self-dual Yang-Mills multiplet with $~N=1~$ supersymmetry in the space-time with signature $(+,+,-,-)$. For this set of constraints, the consistency of the self-duality conditions on these multiplets with supersymmetry is manifest. The energy-momentum tensors of all the self-dual ``matter'' multiplets vanish, to be consistent with the self-duality of the Riemann tensor. In particular, the special significance of the ``self-dual'' tensor multiplet is noted. This result fills the gap left over in our previous series of papers, with respect to the consistent couplings among the self-dual matter multiplets. We also couple these non-trivial backgrounds to a Green-Schwarz superstring $~\s\-$model, under the requirement of invariance under fermionic (kappa) symmetry. The finiteness of the self-dual supergravity is discussed, based on its ``off-shell'' structure. A set of exact solutions for the ``self-dual'' tensor and self-dual Yang-Mills multiplets for the gauge group $~SL(2)$~ on self-dual gravitational instanton background is given, and its consistency with the Green-Schwarz string ~$\s\-$model is demonstrated. | [
"Physics Archive->hep->hep-th"
]
| 1992-11-10T01:45:00Z |
1811.12653 | A graphic approach to gauge invariance induced identity | All tree-level amplitudes in Einstein-Yang-Mills (EYM) theory and gravity (GR) can be expanded in terms of color ordered Yang-Mills (YM) ones whose coefficients are polynomial functions of Lorentz inner products and are constructed by a graphic rule. Once the gauge invariance condition of any graviton is imposed, the expansion of a tree level EYM or gravity amplitude induces a nontrivial identity between color ordered YM amplitudes. Being different from traditional Kleiss-Kuijf (KK) and Bern-Carrasco-Johansson (BCJ) relations, the gauge invariance induced identity includes polarizations in the coefficients. In this paper, we investigate the relationship between the gauge invariance induced identity and traditional BCJ relations. By proposing a refined graphic rule, we prove that all the gauge invariance induced identities for single trace tree-level EYM amplitudes can be precisely expanded in terms of traditional BCJ relations, without referring any property of polarizations. When further considering the transversality of polarizations and momentum conservation, we prove that the gauge invariance induced identity for tree-level GR (or pure YM) amplitudes can also be expanded in terms of traditional BCJ relations for YM (or bi-scalar) amplitudes. As a byproduct, a graph-based BCJ relation is proposed and proved. | [
"Physics Archive->hep->hep-th"
]
| 2018-11-30T07:42:12Z |
2104.08480 | Learning to Share by Masking the Non-shared for Multi-domain Sentiment Classification | Multi-domain sentiment classification deals with the scenario where labeled data exists for multiple domains but insufficient for training effective sentiment classifiers that work across domains. Thus, fully exploiting sentiment knowledge shared across domains is crucial for real world applications. While many existing works try to extract domain-invariant features in high-dimensional space, such models fail to explicitly distinguish between shared and private features at text-level, which to some extent lacks interpretablity. Based on the assumption that removing domain-related tokens from texts would help improve their domain-invariance, we instead first transform original sentences to be domain-agnostic. To this end, we propose the BertMasker network which explicitly masks domain-related words from texts, learns domain-invariant sentiment features from these domain-agnostic texts, and uses those masked words to form domain-aware sentence representations. Empirical experiments on a well-adopted multiple domain sentiment classification dataset demonstrate the effectiveness of our proposed model on both multi-domain sentiment classification and cross-domain settings, by increasing the accuracy by 0.94% and 1.8% respectively. Further analysis on masking proves that removing those domain-related and sentiment irrelevant tokens decreases texts' domain distinction, resulting in the performance degradation of a BERT-based domain classifier by over 12%. | [
"Computer Science Archive->cs.CL"
]
| 2021-04-17T08:15:29Z |
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