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| creation_date
timestamp[ns, tz=UTC] |
|---|---|---|---|---|
1706.01615
|
Brilliant GeV Gamma-ray flash from Inverse Compton Scattering in QED Regime
|
An all-optical scheme is proposed for studying a laser-plasma based incoherent photon emission from inverse Compton scattering in quantum electrodynamic (QED) regime. A theoretical model is presented to explain the coupling effect among radiation reaction trapping, self-generated magnetic field and spiral attractor in phase space, which guarantees the energy and angular momentum (AM) transformation from electromagnetic fields to particles. Taking advantage of a prospective $\sim$10$^{23}$W/cm$^{2}$ laser facility, 3D Particle-in-cell (PIC) simulations manifest the present gamma-ray flash with an unprecedented power of multi-petawatt (PW) and brightness of 1.7$\times$10$^{23}$photons/s/mm$^2$/mrad$^2$/0.1$\%$bandwidth (at 1GeV). These results bode well for new research direction in particle physics and laboratory astrophysics while exploring laser plasma interaction.
|
[
"Physics Archive->physics->physics.plasm-ph"
] | 2017-06-06T06:19:32Z |
1806.00903
|
Neutron to Dark Matter Decay in Neutron Stars
|
Recent proposals have suggested that a previously unknown decay mode of the neutron into a dark matter particle could solve the long lasting measurement problem of the neutron decay width. We show that, if the dark particle in neutron decay is the major component of the dark matter in the universe, this proposal is in disagreement with modern astro-physical data concerning neutron star masses.
|
[
"Physics Archive->nucl->nucl-th"
] | 2018-06-04T00:29:11Z |
hep-ph/0501005
|
Quasilocal Quark Models as Effective Theory of Non-perturbative QCD
|
We consider the Quasilocal Quark Model of NJL type (QNJLM) as an effective theory of non-perturbative QCD including scalar (S), pseudoscalar (P), vector (V) and axial-vector (A) four-fermion interaction with derivatives. In the presence of a strong attraction in the scalar channel the chiral symmetry is spontaneously broken and as a consequence the composite meson states are generated in all channels. With the help of Operator Product Expansion the appropriate set of Chiral Symmetry Restoration (CSR) Sum Rules in these channels are imposed as matching conditions to QCD at intermediate energies. The mass spectrum and some decay constants for ground and excited meson states are calculated.
|
[
"Physics Archive->hep->hep-ph",
"Physics Archive->nucl->nucl-th"
] | 2005-01-02T13:45:24Z |
1902.04284
|
Preparation of a Heteronuclear Two-atom System in the 3D Motional Ground State in an Optical Tweezer
|
We report the realization of a heteronuclear two-atom of $^{87}$Rb-$^{85}$Rb in the ground state of an optical tweezer (OT). Starting by trapping two different isotopic single atoms, a $^{87}$Rb and a $^{85}$Rb in two strongly focused and linearly polarized OT with 4 $\mu$m apart, we perform simultaneously three dimensional Raman sideband cooling for both atoms and the obtained 3D ground state probabilities of $^{87}$Rb and $^{85}$Rb are 0.91(5) and 0.91(10) respectively. There is no obvious crosstalk observed during the cooling process. We then merge them into one tweezer via a species-dependent transport, where the species-dependent potentials are made by changing the polarization of the OTs for each species from linear polarization to the desired circular polarization. The measurable increment of vibrational quantum due to merging is $0.013(1)$ for the axial dimension. This two-atom system can be used to investigate cold collisional physics, to form quantum logic gates, and to build a single heteronuclear molecule. It can also be scaled up to few-atom regime and extended to other atomic species and molecules, and thus to ultracold chemistry.
|
[
"Physics Archive->physics->physics.atom-ph",
"Physics Archive->quant-ph"
] | 2019-02-12T09:04:32Z |
1803.01915
|
Existence of ground states for aggregation-diffusion equations
|
We analyze free energy functionals for macroscopic models of multi-agent systems interacting via pairwise attractive forces and localized repulsion. The repulsion at the level of the continuous description is modeled by pressure-related terms in the functional making it energetically favorable to spread, while the attraction is modeled through nonlocal forces. We give conditions on general entropies and interaction potentials for which neither ground states nor local minimizers exist. We show that these results are sharp for homogeneous functionals with entropies leading to degenerate diffusions while they are not sharp for fast diffusions. The particular relevant case of linear diffusion is totally clarified giving a sharp condition on the interaction potential under which the corresponding free energy functional has ground states or not.
|
[
"Mathematics Archive->math.AP"
] | 2018-03-05T20:30:45Z |
astro-ph/0108309
|
Positional Coincidence between the High-latitude Steady Unidentified Gamma-ray Sources and Possibly Merging Clusters of Galaxies
|
We report an evidence for the first time that merging clusters of galaxies are a promising candidate for the origin of high galactic-latitude, steady unidentified EGRET gamma-ray sources. Instead of using past optical catalogs of eye-selected clusters, we made a matched-filter survey of galaxy clusters over $4\arcdeg \times 4\arcdeg$ areas around seven steady unidentified EGRET sources at $|b|>45\arcdeg$ together with a 100 $\sq \arcdeg$ area near the South Galactic Pole as a control field. In total, 154 Abell-like cluster candidates and 18 close pairs/groups of these clusters, expected to be possibly merging clusters, were identified within estimated redshift $z_{est}\leq 0.15$. Five among the seven EGRET sources have one or two cluster pairs/groups (CPGs) within 1$\arcdeg$ from them. We assess the statistical significance of this result by several methods, and the confidence level of the real excess is maximally 99.8% and 97.8% in a conservative method. In contrast, we found no significant correlation with single clusters. In addition to the spatial correlation, we also found that the richness of CPGs associated with EGRET sources is considerably larger than those of CPGs in the control field. These results imply that a part of the steady unidentified EGRET sources at high-latitude are physically associated with close CPGs, not with single clusters. We also discuss possible interpretations of these results. We argue that, if these associations are real, they are difficult to explain by hadronic processes, but best explained by the inverse-Compton scattering by high energy electrons accelerated in shocks of cluster formation, as recently proposed.
|
[
"Physics Archive->astro-ph"
] | 2001-08-19T21:27:09Z |
2105.04990
|
Weighted Hierarchical Sparse Representation for Hyperspectral Target Detection
|
Hyperspectral target detection has been widely studied in the field of remote sensing. However, background dictionary building issue and the correlation analysis of target and background dictionary issue have not been well studied. To tackle these issues, a \emph{Weighted Hierarchical Sparse Representation} for hyperspectral target detection is proposed. The main contributions of this work are listed as follows. 1) Considering the insufficient representation of the traditional background dictionary building by dual concentric window structure, a hierarchical background dictionary is built considering the local and global spectral information simultaneously. 2) To reduce the impureness impact of background dictionary, target scores from target dictionary and background dictionary are weighted considered according to the dictionary quality. Three hyperspectral target detection data sets are utilized to verify the effectiveness of the proposed method. And the experimental results show a better performance when compared with the state-of-the-arts.
|
[
"Computer Science Archive->cs.CV",
"Electrical Engineering and Systems Science Archive->eess.IV"
] | 2021-05-11T12:50:16Z |
1612.08567
|
Scalable quantum computation based on quantum actuated nuclear-spin decoherence-free qubits
|
We propose a novel architecture for scalable quantum computation based on quantum actuated decoherence-free (DF) qubits. Each qubit is encoded by the DF subspace of a nuclear spin pair and has long coherence time. A nitrogen-vacancy center in diamond is chosen as the quantum actuator to realize initialization, readout and universal control of DF qubits with fidelities higher than 99%. It reduces the challenge of classical interfaces from controlling and observing complex quantum systems down to a simple quantum actuator. Our scheme also provides a novel way to handle complex quantum systems.
|
[
"Physics Archive->quant-ph"
] | 2016-12-27T10:48:27Z |
gr-qc/9408028
|
New Algebraic Methods for Calculating the Heat Kernel and Effective Action in Quantum Gravity and Gauge Theories
|
An overview about recent progress in the calculation of the heat kernel and the one-loop effective action in quantum gravity and gauge theories is given. We analyse the general structure of the standard Schwinger-De Witt asymptotic expansion and discuss the applicability of that to the case of strongly curved manifolds and strong background fields. We argue that the low-energy limit in gauge theories and quantum gravity, when formulated in a covariant way, should be related to background fields with covariantly constant curvature, gauge field strength and potential term. It is shown that the condition of the covariant constancy of the background curvatures brings into existence some Lie algebra. The heat kernel operator for the Laplace operator is presented then as an average over the corresponding Lie group with some nontrivial Gaussian measure. Using this representation the heat kernel diagonal is obtained. The result is expressed purely in terms of curvature invariants and is explicitly covariant. Related topics concerning the structure of symmetric spaces and the calculation of the effective action are discussed.
|
[
"Physics Archive->gr-qc",
"Physics Archive->hep->hep-th"
] | 1994-08-24T14:31:47Z |
1312.7224
|
Flavours in global Klebanov-Witten background
|
We probe flavour branes in the Klebanov-Witten background in global coordinates. We show that supersymmetric probes correspond to massless flavours and analyse their spectrum of fluctuations. Our studies suggest that the mesons are dissociated by the Casimir energy. The spectrum is equidistant, with a ground state given by the conformal dimension of the operator dual to the fluctuations. We show that the equidistant structure of the spectrum arises from the addition of the angular momenta of the fundamental fields composing the meson operators.
|
[
"Physics Archive->hep->hep-th"
] | 2013-12-27T09:46:07Z |
1611.07119
|
Max-Margin Deep Generative Models for (Semi-)Supervised Learning
|
Deep generative models (DGMs) are effective on learning multilayered representations of complex data and performing inference of input data by exploring the generative ability. However, it is relatively insufficient to empower the discriminative ability of DGMs on making accurate predictions. This paper presents max-margin deep generative models (mmDGMs) and a class-conditional variant (mmDCGMs), which explore the strongly discriminative principle of max-margin learning to improve the predictive performance of DGMs in both supervised and semi-supervised learning, while retaining the generative capability. In semi-supervised learning, we use the predictions of a max-margin classifier as the missing labels instead of performing full posterior inference for efficiency; we also introduce additional max-margin and label-balance regularization terms of unlabeled data for effectiveness. We develop an efficient doubly stochastic subgradient algorithm for the piecewise linear objectives in different settings. Empirical results on various datasets demonstrate that: (1) max-margin learning can significantly improve the prediction performance of DGMs and meanwhile retain the generative ability; (2) in supervised learning, mmDGMs are competitive to the best fully discriminative networks when employing convolutional neural networks as the generative and recognition models; and (3) in semi-supervised learning, mmDCGMs can perform efficient inference and achieve state-of-the-art classification results on several benchmarks.
|
[
"Computer Science Archive->cs.CV",
"Computer Science Archive->cs.LG",
"Statistics Archive->stat.ML"
] | 2016-11-22T01:36:29Z |
1811.04217
|
Innovative 3D Depth Map Generation From A Holoscopic 3D Image Based on Graph Cut Technique
|
Holoscopic 3D imaging is a promising technique for capturing full colour spatial 3D images using a single aperture holoscopic 3D camera. It mimics fly's eye technique with a microlens array, which views the scene at a slightly different angle to its adjacent lens that records three dimensional information onto a two dimensional surface. This paper proposes a method of depth map generation from a holoscopic 3D image based on graph cut technique. The principal objective of this study is to estimate the depth information presented in a holoscopic 3D image with high precision. As such, depth map extraction is measured from a single still holoscopic 3D image which consists of multiple viewpoint images. The viewpoints are extracted and utilised for disparity calculation via disparity space image technique and pixels displacement is measured with sub pixel accuracy to overcome the issue of the narrow baseline between the viewpoint images for stereo matching. In addition, cost aggregation is used to correlate the matching costs within a particular neighbouring region using sum of absolute difference SAD combined with gradient-based metric and winner takes all algorithm is employed to select the minimum elements in the array as optimal disparity value. Finally, the optimal depth map is obtained using graph cut technique. The proposed method extends the utilisation of holoscopic 3D imaging system and enables the expansion of the technology for various applications of autonomous robotics, medical, inspection, AR VR, security and entertainment where 3D depth sensing and measurement are a concern.
|
[
"Computer Science Archive->cs.CV"
] | 2018-11-10T08:59:19Z |
2309.03890
|
XpookyNet: Advancement in Quantum System Analysis through Convolutional Neural Networks for Detection of Entanglement
|
The application of machine learning models in quantum information theory has surged in recent years, driven by the recognition of entanglement and quantum states, which are the essence of this field. However, most of these studies rely on existing prefabricated models, leading to inadequate accuracy. This work aims to bridge this gap by introducing a custom deep convolutional neural network (CNN) model explicitly tailored to quantum systems. Our proposed CNN model, the so-called XpookyNet, effectively overcomes the challenge of handling complex numbers data inherent to quantum systems and achieves an accuracy of 98.5%. Developing this custom model enhances our ability to analyze and understand quantum states. However, first and foremost, quantum states should be classified more precisely to examine fully and partially entangled states, which is one of the cases we are currently studying. As machine learning and quantum information theory are integrated into quantum systems analysis, various perspectives, and approaches emerge, paving the way for innovative insights and breakthroughs in this field.
|
[
"Physics Archive->quant-ph"
] | 2023-09-07T17:52:43Z |
2202.06602
|
Neural Re-ranking in Multi-stage Recommender Systems: A Review
|
As the final stage of the multi-stage recommender system (MRS), re-ranking directly affects user experience and satisfaction by rearranging the input ranking lists, and thereby plays a critical role in MRS. With the advances in deep learning, neural re-ranking has become a trending topic and been widely applied in industrial applications. This review aims at integrating re-ranking algorithms into a broader picture, and paving ways for more comprehensive solutions for future research. For this purpose, we first present a taxonomy of current methods on neural re-ranking. Then we give a description of these methods along with the historic development according to their objectives. The network structure, personalization, and complexity are also discussed and compared. Next, we provide benchmarks of the major neural re-ranking models and quantitatively analyze their re-ranking performance. Finally, the review concludes with a discussion on future prospects of this field. A list of papers discussed in this review, the benchmark datasets, our re-ranking library LibRerank, and detailed parameter settings are publicly available at https://github.com/LibRerank-Community/LibRerank.
|
[
"Computer Science Archive->cs.IR"
] | 2022-02-14T10:44:41Z |
1010.3373
|
Instanton Corrected Non-Supersymmetric Attractors
|
We discuss non-supersymmetric attractors with an instanton correction in Type IIA string theory compactified on a Calabi-Yau three-fold at large volume. For a stable non-supersymmetric black hole, the attractor point must minimize the effective black hole potential. We study the supersymmetric as well as non-supersymmetric attractors for the D0-D4 system with instanton corrections. We show that in simple models, like the STU model, the flat directions of the mass matrix can be lifted by a suitable choice of the instanton parameters.
|
[
"Physics Archive->hep->hep-th"
] | 2010-10-16T19:44:34Z |
2104.00083
|
Quantum battery based on quantum discord at room temperature
|
The study of advanced quantum devices for energy storage has attracted the attention of the scientific community in the past few years. Although several theoretical progresses have been achieved recently, experimental proposals of platforms operating as quantum batteries under ambient conditions are still lacking. In this context, this work presents a feasible realization of a quantum battery in a carboxylate-based metal complex, which can store a finite amount of extractable work under the form of quantum discord at room temperature, and recharge by thermalization with a reservoir. Moreover, the stored work can be evaluated through non-destructive measurements of the compound's magnetic susceptibility. These results pave the way for the development of enhanced energy storage platforms through material engineering.
|
[
"Physics Archive->quant-ph"
] | 2021-03-31T19:42:25Z |
cond-mat/9612158
|
Order Parameter and Scaling Fields in Self-Organized Criticality
|
We present a unified dynamical mean-field theory for stochastic self-organized critical models. We use a single site approximation and we include the details of different models by using effective parameters and constraints. We identify the order parameter and the relevant scaling fields in order to describe the critical behavior in terms of usual concepts of non equilibrium lattice models with steady-states. We point out the inconsistencies of previous mean-field approaches, which lead to different predictions. Numerical simulations confirm the validity of our results beyond mean-field theory.
|
[
"Physics Archive->cond-mat->cond-mat.stat-mech"
] | 1996-12-17T17:47:38Z |
hep-th/9612206
|
Time Evolution of Non-Equilibrium Effective Action
|
The time evolution of correlation functions in statistical systems is described by an exact functional differential equation for the corresponding generating functionals. This allows for a systematic discussion of non-equilibrium physics and the approach to equilibrium without the need of solving the nonlinear microscopic equations of motion or computing the time dependence of the probability distribution explicitly.
|
[
"Physics Archive->cond-mat",
"Physics Archive->hep->hep-th"
] | 1996-12-19T18:16:27Z |
astro-ph/0701540
|
Radio variability properties for radio sources
|
In this paper, we used the database of the university of Michigan Radio Astronomy Observatory (UMRAO) at three (4.8 GHz, 8.0 GHZ, and 14.5 GHz) radio frequency to analyze the radio light curves by the power spectral analysis method in search of possible periodicity. The analysis results showed that the radio sources display astrophysically meaningful periodicity ranging from 2.2 to 20.8 years in their light curves at the three frequencies. We also calculated the variability parameters and investigated the correlations between the variability parameter and the flux density. For the variability parameters, we found that the parameters at higher frequency are higher than those in the lower frequency. In addition, the variability parameters of BL Lacertae objects are larger than those of flat-spectrum radio quasars. suggesting that they are more variable than flat spectrum radio quasars.
|
[
"Physics Archive->astro-ph"
] | 2007-01-18T16:46:29Z |
1503.05726
|
Mechanically controlled quantum switch defined on a curved 2DEG
|
To investigate quantum nature of two dimensional electrons subject to high perpendicular magnetic fields, usually a planar electronic Fabry-P\'erot interferometer is utilized. In this work, we investigate an interferometer defined on a curved heterostructure. In the presence of a magnetic field perpendicular to the cylindrical axis, the location and the properties of the edge channels depend on the radial component of the magnetic field. Considering a curved structure, we perform numerical and semi-analytical calculations to determine widths of the incompressible edge states. We observe that the edge states form a closed loop for certain magnetic field strengths yielding observation of conductance oscillations, which can be manipulated by changing the Azimuthal angle mechanically. In addition, we investigate the effect of spin polarization on the edge state distribution considering Zeeman splitting and obtained odd integer edge states. The proposed experiment would yield a novel method to clarify the ongoing debate on the origin of conductance oscillations, namely whether they stem from Aharonov-Bohm phase or charging effects
|
[
"Physics Archive->cond-mat->cond-mat.mes-hall"
] | 2015-03-19T12:00:24Z |
0907.2303
|
Structural tunability in metamaterials
|
We propose a novel approach for efficient tuning of the transmission characteristics of metamaterials through a continuous adjustment of the lattice structure, and confirm it experimentally in the microwave range. The concept is rather general and applicable to various metamaterials as long as the effective medium description is valid. The demonstrated continuous tuning of metamaterial response is highly desirable for a number of emerging applications of metamaterials including sensors, filters, switches, realizable in a wide frequency range.
|
[
"Physics Archive->physics->physics.optics"
] | 2009-07-14T07:44:00Z |
2007.06794
|
ReAD: A Regional Anomaly Detection Framework Based on Dynamic Partition
|
The detection of the abnormal area from urban data is a significant research problem. However, to the best of our knowledge, previous methods designed on spatio-temporal anomalies are road-based or grid-based, which usually causes the data sparsity problem and affects the detection results. In this paper, we proposed a dynamic region partition method to address the above issues. Besides, we proposed an unsupervised REgional Anomaly Detection framework (ReAD) to detect abnormal regions with arbitrary shapes by jointly considering spatial and temporal properties. Specifically, the proposed framework first generate regions via a dynamic region partition method. It keeps that observations in the same region have adjacent locations and similar non-spatial attribute readings, and could alleviate data sparsity and heterogeneity compared with the grid-based approach. Then, an anomaly metric will be calculated for each region by a regional divergence calculation method. The abnormal regions could be finally detected by a weighted approach or a wavy approach according to the different scenario. Experiments on both the simulated dataset and real-world applications demonstrate the effectiveness and practicability of the proposed framework.
|
[
"Computer Science Archive->cs.SI"
] | 2020-07-14T03:37:58Z |
2101.06927
|
Robustness of Meta Matrix Factorization Against Strict Privacy Constraints
|
In this paper, we explore the reproducibility of MetaMF, a meta matrix factorization framework introduced by Lin et al. MetaMF employs meta learning for federated rating prediction to preserve users' privacy. We reproduce the experiments of Lin et al. on five datasets, i.e., Douban, Hetrec-MovieLens, MovieLens 1M, Ciao, and Jester. Also, we study the impact of meta learning on the accuracy of MetaMF's recommendations. Furthermore, in our work, we acknowledge that users may have different tolerances for revealing information about themselves. Hence, in a second strand of experiments, we investigate the robustness of MetaMF against strict privacy constraints. Our study illustrates that we can reproduce most of Lin et al.'s results. Plus, we provide strong evidence that meta learning is essential for MetaMF's robustness against strict privacy constraints.
|
[
"Computer Science Archive->cs.IR"
] | 2021-01-18T08:30:00Z |
1407.7303
|
Remarks on a Liouville-type theorem for Beltrami flows
|
We present a simple, short and elementary proof that if $v$ is a Beltrami flow with a finite energy in $\mathbb R^3$ then $v=0$. In the case of the Beltrami flows satisfying $v\in L^\infty _{loc} (\Bbb R^3) \cap L^q(\Bbb R^3)$ with $q\in [2, 3)$, or $|v(x)|=O(1/|x|^{1+\varepsilon})$ for some $\varepsilon >0$, we provide a different, simple proof that $v=0$.
|
[
"Mathematics Archive->math.AP"
] | 2014-07-28T01:28:48Z |
0903.2233
|
A new apparent quasar pair: Q2225-403A,B
|
We report the serendipitous discovery of a previously unknown quasar at 10.5" from Q2225-403 (z=2.410). The observation of the broad emission line of MgII_2798 and of the surrounding FeII multiplets indicates that the companion quasar is at z=0.932. The spectrum of Q2225-403 shows a number of absorption lines, the most noteworthy is the MgII line at the same redshift of the companion, suggesting that we are probing the gas within the halo ~80 kpc from the closer quasar. From high resolution NIR images we were able to resolve the host galaxies of the two quasars. Basing on the known surface density of quasars in the 2dF survey we estimate that the probability of finding such a close pair is < ~1 per cent.
|
[
"Physics Archive->astro-ph->astro-ph.CO"
] | 2009-03-12T18:15:30Z |
1704.00235
|
Characterizing the Circumgalactic Medium of Nearby Galaxies with HST/COS and HST/STIS Absorption-Line Spectroscopy: II. Methods and Models
|
We present basic data and modeling for a survey of the cool, photo-ionized Circum-Galactic Medium (CGM) of low-redshift galaxies using far-UV QSO absorption line probes. This survey consists of "targeted" and "serendipitous" CGM subsamples, originally described in Stocke et al. (2013, Paper 1). The targeted subsample probes low-luminosity, late-type galaxies at $z<0.02$ with small impact parameters ($\langle\rho\rangle = 71$ kpc), and the serendipitous subsample probes higher luminosity galaxies at $z\lesssim0.2$ with larger impact parameters ($\langle\rho\rangle = 222$ kpc). HST and FUSE UV spectroscopy of the absorbers and basic data for the associated galaxies, derived from ground-based imaging and spectroscopy, are presented. We find broad agreement with the COS-Halos results, but our sample shows no evidence for changing ionization parameter or hydrogen density with distance from the CGM host galaxy, probably because the COS-Halos survey probes the CGM at smaller impact parameters. We find at least two passive galaxies with H I and metal-line absorption, confirming the intriguing COS-Halos result that galaxies sometimes have cool gas halos despite no on-going star formation. Using a new methodology for fitting H I absorption complexes, we confirm the CGM cool gas mass of Paper 1, but this value is significantly smaller than found by the COS-Halos survey. We trace much of this difference to the specific values of the low-$z$ meta-galactic ionization rate assumed. After accounting for this difference, a best-value for the CGM cool gas mass is found by combining the results of both surveys to obtain $\log{(M/M_{\odot})}=10.5\pm0.3$, or ~30% of the total baryon reservoir of an $L \geq L^*$, star-forming galaxy.
|
[
"Physics Archive->astro-ph->astro-ph.CO",
"Physics Archive->astro-ph->astro-ph.GA"
] | 2017-04-01T22:55:01Z |
1009.0874
|
On Climbing Scalars in String Theory
|
In string models with "brane supersymmetry breaking" exponential potentials emerge at (closed-string) tree level but are not accompanied by tachyons. Potentials of this type have long been a source of embarrassment in flat space, but can have interesting implications for Cosmology. For instance, in ten dimensions the logarithmic slope |V'/V| lies precisely at a "critical" value where the Lucchin--Matarrese attractor disappears while the scalar field is \emph{forced} to climb up the potential when it emerges from the Big Bang. This type of behavior is in principle perturbative in the string coupling, persists after compactification, could have trapped scalar fields inside potential wells as a result of the cosmological evolution and could have also injected the inflationary phase of our Universe.
|
[
"Physics Archive->gr-qc",
"Physics Archive->hep->hep-ph",
"Physics Archive->hep->hep-th"
] | 2010-09-04T21:24:31Z |
1103.3253
|
Nonlinear quasimodes near elliptic periodic geodesics
|
We consider the nonlinear Schr\"odinger equation on a compact manifold near an elliptic periodic geodesic. Using a geometric optics construction, we construct quasimodes to a nonlinear stationary problem which are highly localized near the periodic geodesic. We show the nonlinear Schr\"odinger evolution of such a quasimode remains localized near the geodesic, at least for short times.
|
[
"Mathematics Archive->math.AP"
] | 2011-03-16T18:41:13Z |
1806.01686
|
Direct construction of pointlike observables in the Ising model
|
The construction of pointlike fields in quantum integrable models is usually approached by constructing their n-point functions. However, convergence questions of the resulting infinite series remain unresolved even in the simplest case of the massive Ising model. On the other hand, the C*-algebraic approach to the construction considers semi-local bounded operators, but yields local operators only in a very abstract way. We use a novel approach to investigate the structure of these local observables, in the form of smeared pointlike quantum fields. Instead of considering their n-point functions and verifying the Wightman axioms, we establish them as closed operators affiliated with the local C*-algebras. We explicitly construct all pointlike fields of the Ising model, verify the Reeh-Schlieder property and show that they generate the local algebras by dualization.
|
[
"Mathematics Archive->math.MP",
"Physics Archive->math-ph"
] | 2018-06-05T13:38:21Z |
1710.07980
|
Test them all, is it worth it? Assessing configuration sampling on the JHipster Web development stack
|
Many approaches for testing configurable software systems start from the same assumption: it is impossible to test all configurations. This motivated the definition of variability-aware abstractions and sampling techniques to cope with large configuration spaces. Yet, there is no theoretical barrier that prevents the exhaustive testing of all configurations by simply enumerating them, if the effort required to do so remains acceptable. Not only this: we believe there is lots to be learned by systematically and exhaustively testing a configurable system. In this case study, we report on the first ever endeavour to test all possible configurations of an industry-strength, open source configurable software system, JHipster, a popular code generator for web applications. We built a testing scaffold for the 26,000+ configurations of JHipster using a cluster of 80 machines during 4 nights for a total of 4,376 hours (182 days) CPU time. We find that 35.70% configurations fail and we identify the feature interactions that cause the errors. We show that sampling strategies (like dissimilarity and 2-wise): (1) are more effective to find faults than the 12 default configurations used in the JHipster continuous integration; (2) can be too costly and exceed the available testing budget. We cross this quantitative analysis with the qualitative assessment of JHipster's lead developers.
|
[
"Computer Science Archive->cs.SE"
] | 2017-10-22T17:17:15Z |
cmp-lg/9705004
|
Computing Parallelism in Discourse
|
Although much has been said about parallelism in discourse, a formal, computational theory of parallelism structure is still outstanding. In this paper, we present a theory which given two parallel utterances predicts which are the parallel elements. The theory consists of a sorted, higher-order abductive calculus and we show that it reconciles the insights of discourse theories of parallelism with those of Higher-Order Unification approaches to discourse semantics, thereby providing a natural framework in which to capture the effect of parallelism on discourse semantics.
|
[
"Computer Science Archive->cs.CL"
] | 1997-05-01T13:11:42Z |
2208.13494
|
Wigner-Araki-Yanase theorem for continuous and unbounded conserved observables
|
The Wigner-Araki-Yanase (WAY) theorem states that additive conservation laws imply the commutativity of exactly implementable projective measurements and the conserved observables of the system. Known proofs of this theorem are only restricted to bounded or discrete-spectrum conserved observables of the system and are not applicable to unbounded and continuous observables like a momentum operator. In this Letter, we present the WAY theorem for possibly unbounded and continuous conserved observables under the Yanase condition, which requires that the probe positive operator-valued measure should commute with the conserved observable of the probe system. As a result of this WAY theorem, we show that exact implementations of the projective measurement of the position under momentum conservation and of the quadrature amplitude using linear optical instruments and photon counters are impossible. We also consider implementations of unitary channels under conservation laws and find that the conserved observable $L_S$ of the system commute with the implemented unitary $U_S$ if $L_S$ is semi-bounded, while $U_S^\dagger L_S U_S$ can shift up to possibly non-zero constant factor if the spectrum of $L_S$ is upper and lower unbounded. We give simple examples of the latter case, where $L_S$ is a momentum operator.
|
[
"Physics Archive->quant-ph"
] | 2022-08-29T10:55:37Z |
1907.07988
|
Ultrafast lithium diffusion in bilayer buckled graphene: A comparative study of Li and Na
|
The effect of the curvature of bilayer graphene on the interlayer diffusion of Li atoms is investigated using molecular dynamics simulations. A spectacular enhancement of the diffusion constant parallel to the folding axis is found. The ratio of the parallel to the perpendicular diffusion depends on the buckling direction and stacking type, and it increases with the degree of buckling. The strongest anisotropy is observed in the case of fixed zig-zag edges. A comparison with the interlayer diffusion of Na suggests that the strong asymmetry in the vibrational states of buckled graphene and also the smaller mass of Li are likely to contribute to the observed diffusion enhancement. This work opens a new pathway to develop highly-efficient anodes for rechargeable alkaline batteries.
|
[
"Physics Archive->cond-mat->cond-mat.mtrl-sci"
] | 2019-07-18T11:00:21Z |
2009.07868
|
Fiber-compatible photonic feed-forward with 99% fidelity
|
Both photonic quantum computation and the establishment of a quantum internet require fiber-based measurement and feed-forward in order to be compatible with existing infrastructure. Here we present a fiber-compatible scheme for measurement and feed-forward, whose performance is benchmarked by carrying out remote preparation of single-photon polarization states at telecom-wavelengths. The result of a projective measurement on one photon deterministically controls the path a second photon takes with ultrafast optical switches. By placing well-calibrated {bulk} passive polarization optics in the paths, we achieve a measurement and feed-forward fidelity of (99.0 $\pm$ 1)%, after correcting for other experimental errors. Our methods are useful for photonic quantum experiments including computing, communication, and teleportation.
|
[
"Physics Archive->quant-ph"
] | 2020-09-16T18:01:01Z |
2004.12321
|
Federated Transfer Learning for EEG Signal Classification
|
The success of deep learning (DL) methods in the Brain-Computer Interfaces (BCI) field for classification of electroencephalographic (EEG) recordings has been restricted by the lack of large datasets. Privacy concerns associated with EEG signals limit the possibility of constructing a large EEG-BCI dataset by the conglomeration of multiple small ones for jointly training machine learning models. Hence, in this paper, we propose a novel privacy-preserving DL architecture named federated transfer learning (FTL) for EEG classification that is based on the federated learning framework. Working with the single-trial covariance matrix, the proposed architecture extracts common discriminative information from multi-subject EEG data with the help of domain adaptation techniques. We evaluate the performance of the proposed architecture on the PhysioNet dataset for 2-class motor imagery classification. While avoiding the actual data sharing, our FTL approach achieves 2% higher classification accuracy in a subject-adaptive analysis. Also, in the absence of multi-subject data, our architecture provides 6% better accuracy compared to other state-of-the-art DL architectures.
|
[
"Computer Science Archive->cs.LG",
"Electrical Engineering and Systems Science Archive->eess.SP"
] | 2020-04-26T09:03:19Z |
2308.02297
|
Flat blow-up solutions for the complex Ginzburg Landau equation
|
In this paper, we consider the complex Ginzburg Landau equation $$ \partial_t u = (1 + i \beta ) \Delta u + (1 + i \delta) |u|^{p-1}u - \alpha u \text{ where } \beta, \delta, \alpha \in \mathbb R. $$ The study aims to investigate the finite time blowup phenomenon. In particular, for fixed $ \beta\in \mathbb R$, the existence of finite time blowup solutions for an arbitrary large $|\delta|$ is still unknown. Especially, Popp, Stiller, Kuznetsov, and Kramer formally conjectured in 1998 that there is no blowup (collapse) in such a case. In this work, considered as a breakthrough, we give a counter example to this conjecture. We show the existence of blowup solutions in one dimension with $\delta $ arbitrarily given and $\beta =0$. The novelty is based on two main contributions: an investigation of a new blowup scaling (flat blowup regime) and a suitable modulation.
|
[
"Mathematics Archive->math.AP"
] | 2023-08-04T13:02:30Z |
1904.06250
|
Generative Hybrid Representations for Activity Forecasting with No-Regret Learning
|
Automatically reasoning about future human behaviors is a difficult problem but has significant practical applications to assistive systems. Part of this difficulty stems from learning systems' inability to represent all kinds of behaviors. Some behaviors, such as motion, are best described with continuous representations, whereas others, such as picking up a cup, are best described with discrete representations. Furthermore, human behavior is generally not fixed: people can change their habits and routines. This suggests these systems must be able to learn and adapt continuously. In this work, we develop an efficient deep generative model to jointly forecast a person's future discrete actions and continuous motions. On a large-scale egocentric dataset, EPIC-KITCHENS, we observe our method generates high-quality and diverse samples while exhibiting better generalization than related generative models. Finally, we propose a variant to continually learn our model from streaming data, observe its practical effectiveness, and theoretically justify its learning efficiency.
|
[
"Computer Science Archive->cs.AI",
"Computer Science Archive->cs.CV",
"Computer Science Archive->cs.LG"
] | 2019-04-12T14:22:37Z |
1511.08981
|
On Baire classification of mappings with values in connected spaces
|
We generalize the Lebesgue-Hausdorff Theorem on the characterization of Baire-one functions for $\sigma$-strongly functionally discrete mappings defined on arbitrary topological spaces
|
[
"Mathematics Archive->math.GN"
] | 2015-11-29T08:40:33Z |
0811.0874
|
Solitons and vortices in an evolving Bose-Einstein condensate
|
Spatiotemporal evolution of a confined Bose-Einstein condensate is studied by numerically integrating the time-dependent Gross-Pitaevskii equation. Self-interference between the successively expanding and reflecting nonlinear matter waves results in spiral atomic density profile, which subsequently degenerates into an embedding structure: The inner part preserves memory of the initial states while the outer part forms a sequence of necklacelike rings. The phase plot reveals a series of discrete concentric belts. The large gradients between adjacent belts indicate that the ring density notches are dark solitons. In the dynamical process, a scenario of vortex-antivortex pairs are spontaneously created and annihilated, whereas the total vorticity keeps invariant.
|
[
"Physics Archive->cond-mat->cond-mat.supr-con"
] | 2008-11-06T06:12:25Z |
1912.01476
|
From MiniZinc to Optimization Modulo Theories, and Back (Extended Version)
|
Optimization Modulo Theories (OMT) is an extension of SMT that allows for finding models that optimize objective functions. In this paper we aim at bridging the gap between Constraint Programming (CP) and OMT, in both directions. First, we have extended the OMT solver OptiMathSAT with a FlatZinc interface -- which can also be used as a FlatZinc-to-OMT encoder for other OMT solvers. This allows OMT tools to be used in combination with mzn2fzn on the large amount of CP problems coming from the MiniZinc community. Second, we have introduced a tool for translating SMT and OMT problems on the linear arithmetic and bit-vector theories into MiniZinc. This allows MiniZinc solvers to be used on a large amount of SMT/OMT problems. We have discussed the main issues we had to cope with in either directions. We have performed an extensive empirical evaluation comparing three state-of-the-art OMT-based tools with many state-of-the-art CP tools on (i) CP problems coming from the MiniZinc challenge, and (ii) OMT problems coming mostly from formal verification. This analysis also allowed us to identify some criticalities, in terms of efficiency and correctness, one has to cope with when addressing CP problems with OMT tools, and vice versa.
|
[
"Computer Science Archive->cs.LO"
] | 2019-12-03T15:42:26Z |
hep-ph/0606089
|
Grand Unification as a Bridge Between String Theory and Phenomenology
|
In the first part of the talk, I explain what empirical evidence points to the need for having an effective grand unification-like symmetry possessing the symmetry SU(4)-color in 4D. If one assumes the premises of a future predictive theory including gravity--be it string/M theory or a reincarnation--this evidence then suggests that such a theory should lead to an effective grand unification-like symmetry as above in 4D, near the string-GUT-scale, rather than the standard model symmetry. Advantages of an effective supersymmetric G(224) = SU(2)$_L \times$ SU(2)$_R \times$ SU(4)$^c$ or SO(10) symmetry in 4D in explaining (i) observed neutrino oscillations, (ii) baryogenesis via leptogenesis, and (iii) certain fermion mass-relations are noted. And certain distinguishing tests of a SUSY G(224) or SO(10)-framework involving CP and flavor violations (as in $\mu \to e\gamma$, $\tau \to\mu\gamma$, edm's of the neutron and the electron) as well as proton decay are briefly mentioned. Recalling some of the successes we have had in our understanding of nature so far, and the current difficulties of string/M theory as regards the large multiplicity of string vacua, some comments are made on the traditional goal of understanding {\em vis a vis} the recently evolved view of landscape and anthropism.
|
[
"Physics Archive->hep->hep-ph",
"Physics Archive->hep->hep-th"
] | 2006-06-07T23:13:49Z |
astro-ph/0608211
|
A new Cepheid distance to the maser-host galaxy NGC 4258 and its implications for the Hubble Constant
|
We present initial results from a time-series BVI survey of two fields in NGC 4258 using the Advanced Camera for Surveys onboard the Hubble Space Telescope. This galaxy was selected because of its accurate maser-based distance, which is anticipated to have a total uncertainty of ~3%. The goal of the HST observations is to provide an absolute calibration of the Cepheid Distance Scale and to measure its dependence on chemical abundance (the so-called "metallicity effect"). We carried out observations of two fields at different galactocentric distances with a mean abundance difference of 0.5 dex. We discovered a total of 281 Cepheids with periods ranging from 4 to 45 days (the duration of our observing window). We determine a Cepheid distance modulus for NGC 4258 (relative to the LMC) of 10.88 +- 0.04 (random) +- 0.05 (systematic) mag. Given the published maser distance to the galaxy, this implies \mu (LMC)=18.41 +- 0.10 (r) +- 0.13 (s) mag or D(LMC)= 48.1 +- 2.3 (r) +- 2.9 (s) kpc. We measure a metallicity effect of \gamma=-0.29 +- 0.09 (r) +- 0.05 (s) mag/dex. We see no evidence for a variation in the slope of the Period-Luminosity relation as a function of abundance. We estimate a Hubble Constant of H_0= 74 +- 3 (r) +- 6 (s) km/s Mpc using a recent sample of 4 well-observed type Ia SNe and our new calibration of the Cepheid Distance Scale. It may soon be possible to measure the value of H_0 with a total uncertainty of 5%, with consequent improvement in the determination of the equation of state of dark energy.
|
[
"Physics Archive->astro-ph"
] | 2006-08-10T20:00:05Z |
1803.07658
|
Graph-based regularization for regression problems with alignment and highly-correlated designs
|
Sparse models for high-dimensional linear regression and machine learning have received substantial attention over the past two decades. Model selection, or determining which features or covariates are the best explanatory variables, is critical to the interpretability of a learned model. Much of the current literature assumes that covariates are only mildly correlated. However, in many modern applications covariates are highly correlated and do not exhibit key properties (such as the restricted eigenvalue condition, restricted isometry property, or other related assumptions). This work considers a high-dimensional regression setting in which a graph governs both correlations among the covariates and the similarity among regression coefficients -- meaning there is \emph{alignment} between the covariates and regression coefficients. Using side information about the strength of correlations among features, we form a graph with edge weights corresponding to pairwise covariances. This graph is used to define a graph total variation regularizer that promotes similar weights for correlated features. This work shows how the proposed graph-based regularization yields mean-squared error guarantees for a broad range of covariance graph structures. These guarantees are optimal for many specific covariance graphs, including block and lattice graphs. Our proposed approach outperforms other methods for highly-correlated design in a variety of experiments on synthetic data and real biochemistry data.
|
[
"Computer Science Archive->cs.LG",
"Statistics Archive->stat.ML"
] | 2018-03-20T21:07:36Z |
1705.05631
|
Towards quantitative small-scale thermal imaging
|
Quantitative thermal imaging has the potential of reliable temperature measurement across an entire field-of-view. This non-invasive technique has applications in aerospace, manufacturing and process control. However, robust temperature measurement on the sub-millimetre (30 {\mu}m) length scale has yet to be demonstrated. Here, the temperature performance and size-of-source (source size) effect of a 3 {\mu}m to 5 {\mu}m thermal imaging system have been assessed. In addition a technique of quantifying thermal imager non-uniformity is described. An uncertainty budget is constructed, which describes a measurement uncertainty of 640 mK (k = 2) for a target with a size of 10 mm. The results of this study provide a foundation for developing the capability for confident quantitative sub-millimetre thermal imaging.
|
[
"Physics Archive->physics->physics.ins-det"
] | 2017-05-16T10:27:05Z |
2009.11164
|
Detailed studies of IPHAS sources -- III. The highly extinguished bipolar planetary nebula IPHASX J191104.8$+$060845
|
We present the first detailed study of the bipolar planetary nebula (PN) IPHASX J191104.8$+$060845 (PN G040.6$-$01.5) discovered as part of the Isaac Newton Telescope Photometric H$\alpha$ Survey of the Northern Galactic plane (IPHAS). We present Nordic Optical Telescope (NOT) narrow-band images to unveil its true morphology. This PN consists of a main cavity with two newly uncovered extended low-surface brightness lobes located towards the NW and SE directions. Using near-IR WISE images we unveiled the presence of a barrel like structure, which surrounds the main cavity, which would explain the dark lane towards the equatorial regions. We also use Gran Telescopio de Canarias (GTC) spectra to study the physical properties of this PN. We emphasise the potential of old PNe detected in IPHAS to study the final stages of the evolution of the circumstellar medium around solar-like stars.
|
[
"Physics Archive->astro-ph->astro-ph.GA",
"Physics Archive->astro-ph->astro-ph.SR"
] | 2020-09-23T14:22:57Z |
1804.06651
|
Magnetic Flux Control of Chiral Majorana Edge Modes in Topological Superconductor
|
We study the transport of chiral Majorana edge modes (CMEMs) in a hybrid quantum anomalous Hall insulator-topological superconductor (QAHI-TSC) system in which the TSC region contains a Josephson junction and a cavity. The Josephson junction undergoes a topological transition when the magnetic flux through the cavity passes through half-integer multiples of magnetic flux quantum. For the trivial phase, the CMEMs transmit along the QAHI-TSC interface as without magnetic flux. However, for the nontrivial phase, a zero-energy Majorana state appears in the cavity, leading that a CMEM can resonantly tunnel through the Majorana state to a different CMEM. These findings may provide a feasible scheme to control the transport of CMEMs by using the magnetic flux and the transport pattern can be customized by setting the size of the TSC.
|
[
"Physics Archive->cond-mat->cond-mat.mes-hall"
] | 2018-04-18T11:16:43Z |
2309.12863
|
Domain Adaptation for Arabic Machine Translation: The Case of Financial Texts
|
Neural machine translation (NMT) has shown impressive performance when trained on large-scale corpora. However, generic NMT systems have demonstrated poor performance on out-of-domain translation. To mitigate this issue, several domain adaptation methods have recently been proposed which often lead to better translation quality than genetic NMT systems. While there has been some continuous progress in NMT for English and other European languages, domain adaption in Arabic has received little attention in the literature. The current study, therefore, aims to explore the effectiveness of domain-specific adaptation for Arabic MT (AMT), in yet unexplored domain, financial news articles. To this end, we developed carefully a parallel corpus for Arabic-English (AR- EN) translation in the financial domain for benchmarking different domain adaptation methods. We then fine-tuned several pre-trained NMT and Large Language models including ChatGPT-3.5 Turbo on our dataset. The results showed that the fine-tuning is successful using just a few well-aligned in-domain AR-EN segments. The quality of ChatGPT translation was superior than other models based on automatic and human evaluations. To the best of our knowledge, this is the first work on fine-tuning ChatGPT towards financial domain transfer learning. To contribute to research in domain translation, we made our datasets and fine-tuned models available at https://huggingface.co/asas-ai/.
|
[
"Computer Science Archive->cs.AI",
"Computer Science Archive->cs.CL"
] | 2023-09-22T13:37:19Z |
1905.12657
|
Re-awakening of GRS 1716--249 after 23 years, observed by {\it Swift}/XRT and {\it NuSTAR}
|
In this work, we present a spectral and temporal analysis of {\it Swift}/XRT and {\it NuSTAR} observations of GRS 1716--249 during its recent 2016--2017 outburst. This low mass X-ray binary underwent an extraordinary outburst after a long quiescence of 23 years, since its last major outburst in 1993. The source was observed over two different epochs during 2017 April, 07 and 10. The best fit joint spectral fitting in the energy range 0.5 $-$ 79.0 keV indicates that the spectrum is best described by relatively cold, weak disk blackbody emission, dominant thermal Comptonization emission, and a relativistically broadened fluorescent iron K$\alpha$ emission line. We observed a clear indication of a Compton hump around 30 keV. We also detected an excess feature of $\sim1.3$ keV. Assuming a lamp-post geometry of the corona, we constrained the inner disk radius for both observations to 11.92$^{+8.62}_{-11.92}$ R$_{ISCO}$ (i.e., an upper limit) and 10.39$^{+9.51}_{-3.02}$ R$_{ISCO}$ (where R$_{ISCO}\equiv$ radius of the innermost stable circular orbit) for the first epoch (E1) and second epoch (E2), respectively. A significant ($\sim5\sigma$) type$-$C quasi-periodic oscillation (QPO) at $1.20\pm0.04$ Hz is detected for the first time for GRS 1716--249, which drifts to $1.55\pm0.04$ Hz ($\sim6\sigma$) at the end of the second observation. The derived spectral and temporal properties show a positive correlation between the QPO frequency and the photon index.
|
[
"Physics Archive->astro-ph->astro-ph.HE"
] | 2019-05-29T18:07:25Z |
2301.08885
|
An improvement of non-integrated defect relation for meromorphic maps from Kahler manifolds with arbitrary hypersurfaces
|
Our purpose in this paper is to establish a non-integrated defect relation for meromorphic mappings from a complete Kahler manifold into a projective variety intersecting an arbitrary family of hypersurfaces with explicit truncation level. In our result, both the above bound of the total defect and the truncation level are estimated independently of the number of involving hypersurfaces. Our result generalizes and improves the previous results in this topic.
|
[
"Mathematics Archive->math.CV"
] | 2023-01-21T04:17:02Z |
1909.05845
|
DeepPruner: Learning Efficient Stereo Matching via Differentiable PatchMatch
|
Our goal is to significantly speed up the runtime of current state-of-the-art stereo algorithms to enable real-time inference. Towards this goal, we developed a differentiable PatchMatch module that allows us to discard most disparities without requiring full cost volume evaluation. We then exploit this representation to learn which range to prune for each pixel. By progressively reducing the search space and effectively propagating such information, we are able to efficiently compute the cost volume for high likelihood hypotheses and achieve savings in both memory and computation. Finally, an image guided refinement module is exploited to further improve the performance. Since all our components are differentiable, the full network can be trained end-to-end. Our experiments show that our method achieves competitive results on KITTI and SceneFlow datasets while running in real-time at 62ms.
|
[
"Computer Science Archive->cs.CV"
] | 2019-09-12T17:50:04Z |
astro-ph/0103059
|
Stellar populations in the nuclear regions of nearby radiogalaxies
|
We present optical spectra of the nuclei of seven luminous (P(178MHz) > 10**25 W Hz**(-1) Sr**(-1)) nearby (z<0.08) radiogalaxies, which mostly correspond to the FR II class. In two cases, Hydra A and 3C 285, the Balmer and 4000A break indices constrain the spectral types and luminosity classes of the stars involved, revealing that the blue spectra are dominated by blue supergiant and/or giant stars. The ages derived for the last burst of star formation in Hydra A are between 7 and 40 Myr, and in 3C 285 about 10 Myr. The rest of the narrow-line radiogalaxies (four) have 4000A break and metallic indices consistent with those of elliptical galaxies. The only broad-line radiogalaxy in our sample, 3C 382, has a strong featureless blue continuum and broad emission lines that dilute the underlying blue stellar spectra. We are able to detect the Ca II triplet in absorption in the seven objects, with good quality data for only four of them. The strengths of the absorptions are similar to those found in normal elliptical galaxies, but these values are both consistent with single stellar populations of ages as derived from the Balmer absorption and break strengths, and, also, with mixed young+old populations.
|
[
"Physics Archive->astro-ph"
] | 2001-03-04T00:27:26Z |
nucl-th/0601081
|
Ground state of medium-heavy doubly-closed shell nuclei in correlated basis function theory
|
The correlated basis function theory is applied to the study of medium-heavy doubly closed shell nuclei with different wave functions for protons and neutrons and in the jj coupling scheme. State dependent correlations including tensor correlations are used. Realistic two-body interactions of Argonne and Urbana type, together with three-body interactions have been used to calculate ground state energies and density distributions of the 12C, 16O, 40Ca, 48Ca and 208Pb nuclei.
|
[
"Physics Archive->nucl->nucl-th"
] | 2006-01-26T14:42:54Z |
1307.6231
|
On a possible origin for the lack of old star clusters in the Small Magellanic Cloud
|
We model the dynamical interaction between the Small and Large Magellanic Clouds and their corresponding stellar cluster populations. Our goal is to explore whether the lack of old clusters ($\gtrsim 7$ Gyr) in the Small Magellanic Cloud (SMC) can be the result of the capture of clusters by the Large Magellanic Cloud (LMC), as well as their ejection due to the tidal interaction between the two galaxies. For this purpose we perform a suite of numerical simulations probing a wide range of parameters for the orbit of the SMC about the LMC. We find that, for orbital eccentricities $e \geq 0.4$, approximately 15 per cent of the SMC clusters are captured by the LMC. In addition, another 20 to 50 per cent of its clusters are ejected into the intergalactic medium. In general, the clusters lost by the SMC are the less tightly bound cluster population. The final LMC cluster distribution shows a spatial segregation between clusters that originally belonged to the LMC and those that were captured from the SMC. Clusters that originally belonged to the SMC are more likely to be found in the outskirts of the LMC. Within this scenario it is possible to interpret the difference observed between the star field and cluster SMC Age-Metallicity Relationships for ages $\gtrsim 7$ Gyr.
|
[
"Physics Archive->astro-ph->astro-ph.GA"
] | 2013-07-23T20:14:06Z |
1706.06215
|
A $D$-module approach on the equations of the Rees algebra
|
Let $I \subset R = \mathbb{F}[x_1,x_2]$ be a height two ideal minimally generated by three homogeneous polynomials of the same degree $d$, where $\mathbb{F}$ is a field of characteristic zero. We use the theory of $D$-modules to deduce information about the defining equations of the Rees algebra of $I$. Let $\mathcal{K}$ be the kernel of the canonical map $\alpha: \text{Sym}(I) \rightarrow \text{Rees}(I)$ from the symmetric algebra of $I$ onto the Rees algebra of $I$. We prove that $\mathcal{K}$ can be described as the solution set of a system of differential equations, that the whole bigraded structure of $\mathcal{K}$ is characterized by the integral roots of certain $b$-functions, and that certain de Rham cohomology groups can give partial information about $\mathcal{K}$.
|
[
"Mathematics Archive->math.AC",
"Mathematics Archive->math.AG"
] | 2017-06-19T23:26:09Z |
hep-ph/0411007
|
A sum rule for elastic scattering
|
A sum rule is derived for elastic scattering of hadrons at high energies which is in good agreement with experimental data on $p\bar{p}$ available upto the maximum energy $\sqrt{s} = 2 TeV$. Physically, our sum rule reflects the way unitarity correlates and limits how large the elastic amplitude can be as a function of energy to how fast it decreases as a function of the momentum transfer. The universality of our result is justified through our earlier result on equipartition of quark and glue momenta obtained from the virial theorem for massless quarks and the Wilson conjecture
|
[
"Physics Archive->hep->hep-ph"
] | 2004-10-30T20:21:55Z |
astro-ph/0211035
|
Caught in the act: a helium-reionizing quasar near the line of sight to Q0302-003
|
We report the discovery of a quasar at z=3.050+/-0.003, closely coincident in redshift with the isolated low-opacity feature seen near z~3.056 in the otherwise black portion of the HeII Gunn-Peterson absorption trough seen toward the z=3.286 background quasar Q0302-003, located 6.5' away on the sky. We explore plausible models for the HeIII ionization zone created by this neighboring quasar and its interception with the line of sight toward Q0302-003. At its present brightness of V=20.5 and separation of D=3.2 Mpc, the quasar can readily account for the opacity gap in the HeII absorption spectrum of Q0302-003, provided it has been active for t_Q > 10^7 y. This is the first clear detection of the `transverse' proximity effect and imprint of a quasar on the intervening absorption detected along an adjacent line of sight.
|
[
"Physics Archive->astro-ph"
] | 2002-11-03T12:29:21Z |
1510.07548
|
Weak ferromagnetism and magnetization reversal in YFe$_{1-x}$Cr$_x$O$_3$
|
We present combined experimental and theoretical studies on the magnetic properties of a solid solution between yttrium orthoferrite and yttrium orthochromite systems, YFe$_{1-x}$Cr$_x$O$_3$ (0 $\leq$ x $\leq$ 1) where Fe$^{3+}$ and Cr$^{3+}$ ions are distributed randomly at the same crystallographic site (4b). We found that all the compositions exhibit weak ferromagnetism below the N\'eel temperature that decreases non-linearly with increasing $x$, while certain intermediate compositions ($x = 0.4,0.5$) show a compensation point and magnetization reversal. This unusual behavior is explained based on a simple model comprising the isotropic superexchange and the antisymmetric Dzyaloshinskii-Moriya interactions. This model explains the magnetization behavior in the entire range of doping and temperature including the magnetization reversal which results from an interplay of various DM interactions such as, Fe-O-Fe, Cr-O-Cr and Fe-O-Cr.
|
[
"Physics Archive->cond-mat->cond-mat.str-el"
] | 2015-10-26T16:58:46Z |
cond-mat/0302120
|
Enhancement of Jc by doping silver in grain boundaries of YBa2Cu3Oy polycrystals with solid-state diffusion method
|
Grain boundaries (GBs) of YBa2Cu3Oy (YBCO) are preferentially doped with Ag by the solid-state diffusion method. The distribution of Ag is highly localized in the GB. As a result of the Ag doping, the Jc-H behavior of YBCO textured polycrystalline samples is significantly improved, and at 60 K and 7 T, Jc is tripled. It is proposed that Ag could partially replace the Cu in CuO2 planes near GBs, therefore reducing the geometric distortion of Cu-O bonds and making the effective GBs thinner.
|
[
"Physics Archive->cond-mat->cond-mat.supr-con"
] | 2003-02-06T11:46:00Z |
2005.05664
|
Room-temperature operation of a molecular spin photovoltaic device on a transparent substrate
|
Incorporating multifunctionality along with the spin-related phenomenon in a single device is of great interest for the development of next generation spintronic devices. One of these challenges is to couple the photo-response of the device together with its magneto-response to exploit the multifunctional operation at room temperature. Here, the multifunctional operation of a single layer p-type molecular spin valve is presented, where the device shows a photovoltaic effect at the room temperature on a transparent glass substrate. The generated photovoltage is almost three times larger than the applied bias to the device which facilitates the modulation of the magnetic response of the device both with bias and light. It is observed that the photovoltage modulation with light and magnetic field is linear with the light intensity. The device shows an increase in power conversion efficiency under magnetic field, an ability to invert the current with magnetic field and under certain conditions it can act as a spin-photodetector with zero power consumption in the standby mode. The room temperature exploitation of the interplay among light, bias and magnetic field in the single device with a p-type molecule opens a way towards more complex and efficient operation of a complete spin-photovoltaic cell.
|
[
"Physics Archive->cond-mat->cond-mat.mes-hall",
"Physics Archive->physics->physics.app-ph"
] | 2020-05-12T10:20:08Z |
1807.11744
|
High Resolution Imaging of the Magnetic Field in the central parsec of the Galaxy
|
We discuss a high resolution (FWHM~ 0.45 arcsec) image of the emissive polarization from warm dust in the minispiral in the Galactic Centre and discuss the implications for the magnetic field in the dusty filaments. The image was obtained at a wavelength of 12.5 microns with the CanariCam multimode mid-infrared imager on the Gran Telescopio Canarias. It confirms the results obtained from previous observations but also reveals new details of the polarization structures. In particular, we identify regions of coherent magnetic field emission at position angles of ~45 deg to the predominantly north--south run of field lines in the Northern Arm which may be related to orbital motions inclined to the general flow of the Northern Arm. The luminous stars that have been identified as bow-shock sources in the Northern Arm do not disrupt or dilute the field but are linked by a coherent field structure, implying that the winds from these objects may push and compress the field but do not overwhelm it. The magnetic field in the the low surface brightness regions in the East-West Bar to the south of SgrA* lies along the Bar, but the brighter regions generally have different polarization position angles, suggesting that they are distinct structures. In the region of the Northern Arm sampled here, there is only a weak correlation between the intensity of the emission and the degree of polarization. This is consistent with saturated grain alignment where the degree of polarization depends on geometric effects, including the angle of inclination of the field to the line of sight and superposition of filaments with different field directions, rather than the alignment efficiency.
|
[
"Physics Archive->astro-ph->astro-ph.GA"
] | 2018-07-31T10:19:12Z |
2308.12286
|
Fixed point conditions for non-coprime actions
|
In the setting of finite groups, suppose $J$ acts on $N$ via automorphisms so that the induced semidirect product $N\rtimes J$ acts on some non-empty set $\Omega$, with $N$ acting transitively. Glauberman proved that if the orders of $J$ and $N$ are coprime, then $J$ fixes a point in $\Omega$. We consider the non-coprime case and show that if $N$ is abelian and a Sylow $p$-subgroup of $J$ fixes a point in $\Omega$ for each prime $p$, then $J$ fixes a point in $\Omega$. We also show that if $N$ is nilpotent, $N\rtimes J$ is supersoluble, and a Sylow $p$-subgroup of $J$ fixes a point in $\Omega$ for each prime $p$, then $J$ fixes a point in $\Omega$.
|
[
"Mathematics Archive->math.GR"
] | 2023-08-23T17:58:26Z |
0908.0548
|
IPv6 and IPv4 Threat reviews with Automatic Tunneling and Configuration Tunneling Considerations Transitional Model:A Case Study for University of Mysore Network
|
The actual transition from IPv4 to IPv6 requires network administrators to become aware of the next generation protocol and the associated risk problems.Due to the scale and complexity of current internet architecture how to protect from the existing investment and reduce the negative influence to users and service providers during the transition from IPv4 to IPv6 is a very important future topic for the advanced version of an internet architecture.This paper summarizes and compares the IPv6 transition mechanism methods like Dual Stack,Tunneling issues like IPv6 Automatic tunneling and manually configured tunneling considerations, the IPv6 transition scenarios,IPv6 transition security problems,highlights IPv6 and IPv4 threat review with automatic tunneling and configuration tunneling considerations.In this paper we have proposed a transitional threat model for automatic tunneling and a configuration tunneling that could be followed by the University of Mysore(UoM),to estimate automatic tunneling and a manually configured tunneling threat review issues.Furthermore,there are different tunneling mechanisms such as IPv6 over IPv4 GRE Tunnel,Tunnel broker,Automatic IPv4 Compatible Tunnel and Automatic 6 to 4 Tunnel and also outlines many of the common known threats against IPv6 and then it compares and contrast how these threats are similar ones,might affect an IPv6 network.
|
[
"Computer Science Archive->cs.CR",
"Computer Science Archive->cs.NI"
] | 2009-08-04T21:12:21Z |
2310.16951
|
The Teenager's Problem: Efficient Garment Decluttering With Grasp Optimization
|
This paper addresses the ''Teenager's Problem'': efficiently removing scattered garments from a planar surface. As grasping and transporting individual garments is highly inefficient, we propose analytical policies to select grasp locations for multiple garments using an overhead camera. Two classes of methods are considered: depth-based, which use overhead depth data to find efficient grasps, and segment-based, which use segmentation on the RGB overhead image (without requiring any depth data); grasp efficiency is measured by Objects per Transport, which denotes the average number of objects removed per trip to the laundry basket. Experiments suggest that both depth- and segment-based methods easily reduce Objects per Transport (OpT) by $20\%$; furthermore, these approaches complement each other, with combined hybrid methods yielding improvements of $34\%$. Finally, a method employing consolidation (with segmentation) is considered, which manipulates the garments on the work surface to increase OpT; this yields an improvement of $67\%$ over the baseline, though at a cost of additional physical actions.
|
[
"Computer Science Archive->cs.RO"
] | 2023-10-25T19:36:28Z |
1308.4819
|
Tailored two-photon correlation and fair-sampling: a cautionary tale
|
We demonstrate an experimental test of the Clauser-Horne-Shimony-Holt (CHSH) Bell inequality which seemingly exhibits correlations beyond the limits imposed by quantum mechanics. Inspired by the idea of Fourier synthesis, we design analysers that measure specific superpositions of orbital angular momentum (OAM) states, such that when one analyser is rotated with respect to the other, the resulting coincidence curves are similar to a square-wave. Calculating the CHSH Bell parameter, $S$, from these curves result to values beyond the Tsirelson bound of $S_{QM}=2\sqrt{2}$. We obtain $S=3.99\pm0.02$, implying almost perfect nonlocal Popescu-Rohrlich correlations. The "super-quantum" values of $S$ is only possible in our experiment because our experiment, subtly, does not comply with fair-sampling. The way our Bell test fails fair-sampling is not immediately obvious and requires knowledge of the states being measured. Our experiment highlights the caution needed in Bell-type experiments based on measurements within high-dimensional state spaces such as that of OAM, especially in the advent of device-independent quantum protocols.
|
[
"Physics Archive->quant-ph"
] | 2013-08-22T10:45:17Z |
0912.1463
|
Bound states in two-dimensional spin systems near the Ising limit: A quantum finite-lattice study
|
We analyze the properties of low-energy bound states in the transverse-field Ising model and in the XXZ model on the square lattice. To this end, we develop an optimized implementation of perturbative continuous unitary transformations. The Ising model is studied in the small-field limit which is found to be a special case of the toric code model in a magnetic field. To analyze the XXZ model, we perform a perturbative expansion about the Ising limit in order to discuss the fate of the elementary magnon excitations when approaching the Heisenberg point.
|
[
"Physics Archive->cond-mat->cond-mat.str-el",
"Physics Archive->quant-ph"
] | 2009-12-08T12:03:12Z |
1312.5599
|
Analysis of higher spin black holes with spin-4 chemical potential
|
We consider the $AdS_{3}/CFT_{2}$ duality between certain coset WZW theories at large central charge and Vasiliev 3D higher spin gravity with a single complex field. On the gravity side, we discuss a higher spin black hole solution with chemical potential coupled to the spin-4 charge. We compute the perturbative expansion of the higher spin charges and of the partition function at high order in the chemical potential. The result is obtained with its exact dependence on the parameter $\lambda$ characterising the symmetry algebra $\mbox{hs}[\lambda]$. The cases of $\lambda=0,1$ are successfully compared with a CFT calculation. The special point $\lambda=\infty$, the Bergshoeff-Blencowe-Stelle limit, is also solved in terms of the exact generating function for the partition function. The thermodynamics of both the spin-4 and the usual spin-3 black holes is studied in order to discuss the $\lambda$ dependence of the BTZ critical temperature $T_{\rm BTZ}(\lambda)$. In the spin-3 case, it is shown that $T_{\rm BTZ}(\lambda)$ converges for large $\lambda$ to the critical point of the $\lambda=\infty$ known partition function previously found by the authors. In the spin-4 black hole, the picture is qualitatively similar and $T_{\rm BTZ}(\infty)$ is accurately determined by various numerical methods.
|
[
"Physics Archive->hep->hep-th"
] | 2013-12-19T15:57:26Z |
2308.10604
|
BackTrack: Robust template update via Backward Tracking of candidate template
|
Variations of target appearance such as deformations, illumination variance, occlusion, etc., are the major challenges of visual object tracking that negatively impact the performance of a tracker. An effective method to tackle these challenges is template update, which updates the template to reflect the change of appearance in the target object during tracking. However, with template updates, inadequate quality of new templates or inappropriate timing of updates may induce a model drift problem, which severely degrades the tracking performance. Here, we propose BackTrack, a robust and reliable method to quantify the confidence of the candidate template by backward tracking it on the past frames. Based on the confidence score of candidates from BackTrack, we can update the template with a reliable candidate at the right time while rejecting unreliable candidates. BackTrack is a generic template update scheme and is applicable to any template-based trackers. Extensive experiments on various tracking benchmarks verify the effectiveness of BackTrack over existing template update algorithms, as it achieves SOTA performance on various tracking benchmarks.
|
[
"Computer Science Archive->cs.AI",
"Computer Science Archive->cs.CV",
"Computer Science Archive->cs.LG"
] | 2023-08-21T10:00:59Z |
2302.09609
|
An Addendum to the Problem of Zero-Sum LQ Stochastic Mean-Field Dynamic Games\\ (Extended version)
|
In this paper, we first address a linear quadratic mean-field game problem with a leader-follower structure. By adopting a Riccati-type approach, we show how one can obtain a state-feedback representation of the pairs of strategies which achieve an open-loop Stackelberg equilibrium in terms of the global solutions of a system of coupled matrix differential Riccati-type equations. In the second part of this paper, we obtain necessary and sufficient conditions for the solvability of the involved coupled generalized Riccati equations.
|
[
"Computer Science Archive->cs.SY",
"Electrical Engineering and Systems Science Archive->eess.SY"
] | 2023-02-19T16:10:23Z |
hep-th/9406207
|
String Field Theory in the Temporal Gauge
|
We construct the string field Hamiltonian for $c=1-\frac{6}{m(m+1)}$ string theory in the temporal gauge. In order to do so, we first examine the Schwinger-Dyson equations of the matrix chain models and propose the continuum version of them. Results of boundary conformal field theory are useful in making a connection between the discrete and continuum pictures. The $W$ constraints are derived from the continuum Schwinger-Dyson equations. We also check that these equations are consistent with other known results about noncritical string theory. The string field Hamiltonian is easily obtained from the continuum Schwinger-Dyson equations. It looks similar to Kaku-Kikkawa's Hamiltonian and may readily be generalized to $c>1$ cases.
|
[
"Physics Archive->hep->hep-th"
] | 1994-06-30T14:17:28Z |
0907.3037
|
Every P-convex subset of $\R^2$ is already strongly P-convex
|
A classical result of Malgrange says that for a polynomial P and an open subset $\Omega$ of $\R^d$ the differential operator $P(D)$ is surjective on $C^\infty(\Omega)$ if and only if $\Omega$ is P-convex. H\"ormander showed that $P(D)$ is surjective as an operator on $\mathscr{D}'(\Omega)$ if and only if $\Omega$ is strongly P-convex. It is well known that the natural question whether these two notions coincide has to be answered in the negative in general. However, Tr\`eves conjectured that in the case of d=2 P-convexity and strong P-convexity are equivalent. A proof of this conjecture is given in this note.
|
[
"Mathematics Archive->math.AP",
"Mathematics Archive->math.FA"
] | 2009-07-17T10:29:53Z |
hep-ex/0605003
|
Dalitz plot analysis of the decay B+- -> K+-K+-K-+
|
We analyze the three-body charmless decay B+- -> K+-K+-K-+ using a sample of 226.0 +- 2.5 million BBbar pairs collected by the BABAR detector. We measure the total branching fraction and CP asymmetry to be B = (35.2 +- 0.9 +-1.6) x 10^{-6} and A_CP = (-1.7 +- 2.6 +- 1.5)%. We fit the Dalitz plot distribution using an isobar model and measure the magnitudes and phases of the decay coefficients. We find no evidence of CP violation for the individual components of the isobar model. The decay dynamics is dominated by the K+K- S-wave, for which we perform a partial-wave analysis in the region m(K+K-) < 2 GeV/c^2. Significant production of the f0(980) resonance, and of a spin zero state near 1.55 GeV/c^2 are required in the isobar model description of the data. The partial-wave analysis supports this observation.
|
[
"Physics Archive->hep->hep-ex"
] | 2006-04-29T09:48:36Z |
1904.04345
|
Hawking--Unruh Radiation from the relics of the cosmic quark hadron phase transition
|
It is entirely plausible that during the primordial quark-hadron transition, microseconds after the Big Bang, the universe may experience supercooling accompanied by mini inflation leading to a first-order phase transition from quarks to hadrons. The relics, in the form of quark nuggets expected to consist of Strange Quark Matter, with a baryon number beyond a critical value will survive. It is conjectured that color confinement turns the physical vacuum to an event horizon for quarks and gluons. The horizon can be crossed only by quantum tunnelling. The process just mentioned is the QCD counterpart of Hawking radiation from gravitational black holes. Thus, when the Hawking temperature of the quark nuggets gets turned off, tunnelling will stop and the nuggets will survive forever. The baryon number and the mass of these nuggets are derived using this theoretical format. The results agree well with the prediction using other phenomenological models. Further, the variation of Hawking temperature as a function of baryon number and mass of the nugget mimicks chiral phase transition, somewhat similar to the QCD phase transition just described. Finally the strange quark nuggets may well be the candidates of baryonic dark matter.
|
[
"Physics Archive->physics->physics.gen-ph"
] | 2019-03-25T05:17:07Z |
1005.5017
|
Lattice Distortion to Stabilize the Spin-Peierls State in CeRu2Al10
|
We propose a relevant lattice distortion to stabilize the spin-Peierls state in CeRu2Al10, compatible with the 27Al-NQR spectra and the neutron diffraction patterns on the assumption that Al atoms at Al(1) to Al(4) sites displace toward their respective neighboring Ce ions below T0 = 27 K, leaving Ce, Ru, and Al at Al(5) immobile. Due to a resulting regular lattice distortion the assembly of one-dimensional spin-Peierls order on each zigzag chain along the c-axis predicted by the author becomes a three-dimensional order with Q = (0, 0, 1), where bonds connecting dimerized pair of Ce ions form an antiferro ordering in a body-centered structure.
|
[
"Physics Archive->cond-mat->cond-mat.str-el"
] | 2010-05-27T10:03:14Z |
0910.2018
|
Suppression of oscillations by Levy noise
|
We find analytical solution of pair of stochastic equations with arbitrary forces and multiplicative L\'evy noises in a steady-state nonequilibrium case. This solution shows that L\'evy flights suppress always a quasi-periodical motion related to the limit cycle. We prove that difference between stochastic systems driven by L\'evy and Gaussian noises is that the L\'evy variation $\Delta L\sim(\Delta t)^{1/\alpha}$ with the exponent $\alpha<2$ is much less than the Gaussian one $\Delta W\sim(\Delta t)^{1/2}$ in the $\Delta t\to 0$ limit. Moreover, this difference is shown to remove the problem of the calculus choice because related addition to the physical force is of order $(\Delta t)^{2/\alpha}\ll\Delta t$.
|
[
"Physics Archive->cond-mat->cond-mat.stat-mech"
] | 2009-10-11T16:30:38Z |
1301.0985
|
Some applications of Grothendieck Duality Theorem
|
In this paper, we systematically apply Grothendieck duality theorem to simplify the proofs of several theorems in different papers: Including a vanishing theorem in KMM, a theorem of Koll\'{a}r's paper, a vanishing theorem due to Kov\'{a}cs and a theorem of Fujino. We remark that all of the above are achieved by the same trick.
|
[
"Mathematics Archive->math.AG"
] | 2013-01-06T08:15:46Z |
1406.2802
|
Unusual swelling of a polymer in a bacterial bath
|
The equilibrium structure and dynamics of a single polymer chain in a thermal solvent is by now well-understood in terms of scaling laws. Here we consider a polymer in a bacterial bath, i.e. in a solvent consisting of active particles which bring in nonequilibrium fluctuations. Using computer simulations of a self-avoiding polymer chain in two dimensions which is exposed to a dilute bath of active particles, we show that the Flory-scaling exponent is unaffected by the bath activity provided the chain is very long. Conversely, for shorter chains, there is a nontrivial coupling between the bacteria intruding into the chain which may stiffen and expand the chain in a nonuniversal way. As a function of the molecular weight, the swelling first scales faster than described by the Flory exponent, then an unusual plateau-like behaviour is reached and finally a crossover to the universal Flory behaviour is observed. As a function of bacterial activity, the chain end-to-end distance exhibits a pronounced non-monotonicity. Moreover, the mean-square displacement of the center of mass of the chain shows a ballistic behaviour at intermediate times as induced by the active solvent. Our predictions are verifiable in two-dimensional bacterial suspensions and for colloidal model chains exposed to artificial colloidal microswimmers.
|
[
"Physics Archive->cond-mat->cond-mat.soft",
"Physics Archive->cond-mat->cond-mat.stat-mech"
] | 2014-06-11T07:31:42Z |
1907.11008
|
Macroscopic manifestations of rotating triaxial superfluid nuclei
|
Recently, Allmond and Wood [Phys. Lett. B 767, 226 (2017)] were able to extract the three moments of inertia $I_k$ of a dozen of superfluid triaxial nuclei from experimental data. The observed dependence of the $I_k$ on the deformation parameters is rather smooth. Here we show that these moments of inertia can be surprisingly well explained by a semiclassical cranked Hartree-Fock-Bogoliubov (HFB) calculation in which the velocity field is a simple superposition of rigid and irrotational flows.
|
[
"Physics Archive->nucl->nucl-th"
] | 2019-07-25T12:31:57Z |
1204.0398
|
IR color separation in transmission through gratings on (110) silicon: FTIR experiment versus theory
|
The phenomenon of filtering in zero-diffraction order is studied for transmission through 1D-periodic structures on a silicon wafer. Our study combines FTIR spectrometry in the range from 2.5 to 25 microns, and a rigorous full-vector simulation. The phenomenon exhibits itself as 'bright' and 'dark' bands in the spectra of normal transmission through grating samples, which replace each other quasi-periodically with respect to wave number, at wavelengths smaller than the grating period. The transmission modulation ratio is extremely high for two-side polished samples. Good agreement between the rigorous theory and experiment both in the range of the transmission oscillations and in the region of enhanced absorption is obtained
|
[
"Physics Archive->cond-mat->cond-mat.mtrl-sci",
"Physics Archive->physics->physics.optics"
] | 2012-04-02T13:11:05Z |
1111.6536
|
Weak Values: Approach through the Clifford and Moyal Algebras
|
In this paper we calculate various transition probability amplitudes, TPAs, known as `weak values' for the Schrodinger and Pauli particles. It is shown that these values are related to the Bohm momentum, the Bohm energy and the quantum potential in each case. The results for the Schrodinger particle are obtained in three ways, the standard approach, the Clifford algebra approach of Hiley and Callaghan, and the Moyal approach. To obtain the results for the Pauli particle, we combine the Clifford and Moyal algebras into one structure. The consequences of these results are discussed.
|
[
"Physics Archive->quant-ph"
] | 2011-11-28T18:25:02Z |
0807.3235
|
A Connection on Manifolds with a Nilpotent Structure
|
All the connections, pure toward the nilpotent structure, are found. Examples of manifolds, for which the curvature tensor is pure or hybrid, are given. For a manifold of B-type a necessary and sufficient condition for purity of the curvature tensor is proved. It is verified that the conformal change of the metric of a B-manifold does not retain its purity.
|
[
"Mathematics Archive->math.DG"
] | 2008-07-21T10:51:46Z |
1709.10264
|
Measurement of the cross-section for electroweak production of dijets in association with a $Z$ boson in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
|
The cross-section for the production of two jets in association with a leptonically decaying Z boson ($Zjj$) is measured in proton-proton collisions at a centre-of-mass energy of 13 TeV, using data recorded with the ATLAS detector at the Large Hadron Collider, corresponding to an integrated luminosity of 3.2 fb$^{-1}$. The electroweak $Zjj$ cross-section is extracted in a fiducial region chosen to enhance the electroweak contribution relative to the dominant Drell-Yan $Zjj$ process, which is constrained using a data-driven approach. The measured fiducial electroweak cross-section is $\sigma^{Zjj}_{EW}= 119\pm 16 (\mathrm{stat.}) \pm 20 (\mathrm{syst.})\pm 2 (\mathrm{lumi.})$ for dijet invariant mass greater than 250 GeV, and $34.2\pm 5.8 (\mathrm{stat.})\pm 5.5 (\mathrm{syst.})\pm 0.7 (\mathrm{lumi.})$ for dijet invariant mass greater than 1 TeV. Standard Model predictions are in agreement with the measurements. The inclusive $Zjj$ cross-section is also measured in six different fiducial regions with varying contributions from electroweak and Drell-Yan $Zjj$ production.
|
[
"Physics Archive->hep->hep-ex"
] | 2017-09-29T07:34:40Z |
1102.4172
|
Kazhdan-Lusztig parameters and extended quotients
|
The Kazhdan-Lusztig parameters are important parameters in the representation theory of $p$-adic groups and affine Hecke algebras. We show that the Kazhdan-Lusztig parameters have a definite geometric structure, namely that of the extended quotient $T//W$ of a complex torus $T$ by a finite Weyl group $W$. More generally, we show that the corresponding parameters, in the principal series of a reductive $p$-adic group with connected centre, admit such a geometric structure. This confirms, in a special case, our recently formulated geometric conjecture. In the course of this study, we provide a unified framework for Kazhdan-Lusztig parameters on the one hand, and Springer parameters on the other hand. Our framework contains a complex parameter $s$, and allows us to interpolate between $s = 1$ and $s = \sqrt q$. When $s = 1$, we recover the parameters which occur in the Springer correspondence; when $s = \sqrt q$, we recover the Kazhdan-Lusztig parameters.
|
[
"Mathematics Archive->math.RT"
] | 2011-02-21T09:43:36Z |
1708.03300
|
Search for Close Stellar Encounters with the Solar System from Data on Nearby Dwarfs
|
Trigonometric parallaxes measured with ground-based telescopes of the RECONS consortium as part of the CTIOPI program are used to search for stars that have either had an encounter with the solar system in the past or will have such an encounter in the future, at distances of less than a few parsecs. These are mainly low-mass dwarfs and subdwarfs of types M, L, and T currently at distances of less than 30 pc from the Sun. Six stars for which encounters with the solar orbit at distances of less than 1 pc are possible have been identified for the first time. For example, the minimum distance for the star **SOZ 3A will 0.72+/- 0.11 pc at an epoch of 103+/-44 thousand years in the future.
|
[
"Physics Archive->astro-ph->astro-ph.GA"
] | 2017-08-10T17:05:29Z |
1009.0491
|
Higher derivative corrections in holographic Zamolodchikov-Polchinski theorem
|
We study higher derivative corrections in holographic dual of Zamolodchikov-Polchinski theorem that states the equivalence between scale invariance and conformal invariance in unitary d-dimensional Poincare invariant field theories. From the dual holographic perspective, we find that a sufficient condition to show the holographic theorem is the generalized strict null energy condition of the matter sector in effective (d+1)-dimensional gravitational theory. The same condition has appeared in the holographic dual of the "c-theorem" and our theorem suggests a deep connection between the two, which was manifested in two-dimensional field theoretic proof of the both.
|
[
"Physics Archive->hep->hep-th"
] | 2010-09-02T18:00:18Z |
2208.12996
|
A Federated Learning-enabled Smart Street Light Monitoring Application: Benefits and Future Challenges
|
Data-enabled cities are recently accelerated and enhanced with automated learning for improved Smart Cities applications. In the context of an Internet of Things (IoT) ecosystem, the data communication is frequently costly, inefficient, not scalable and lacks security. Federated Learning (FL) plays a pivotal role in providing privacy-preserving and communication efficient Machine Learning (ML) frameworks. In this paper we evaluate the feasibility of FL in the context of a Smart Cities Street Light Monitoring application. FL is evaluated against benchmarks of centralised and (fully) personalised machine learning techniques for the classification task of the lampposts operation. Incorporating FL in such a scenario shows minimal performance reduction in terms of the classification task, but huge improvements in the communication cost and the privacy preserving. These outcomes strengthen FL's viability and potential for IoT applications.
|
[
"Computer Science Archive->cs.CV",
"Computer Science Archive->cs.LG"
] | 2022-08-27T12:26:25Z |
1809.01381
|
Charge Transport Behavior of 1D Gold Chiral Nanojunctions
|
Understanding the process of electron tunneling in chirality-induced single-molecule junctions is imperative for the development of nanoscale switching and artificial nanomotors. Based on the combined non-equilibrium Green functions formalism and the ground-state density functional theory, we present here the charge transport behavior of chiral gold (7,3) nanowires (NWs) in comparison with various other chiral and achiral 1D gold nanostructures as the principal leads to form stable single-molecule junctions. For sigma-saturated alkane chains, we find that the contact potential barriers vary widely with the achiral leads but not with the chiral ones, although a close resemblance exists in the tunneling constants. Lower energy gaps for single-molecule junctions with Au(7,3)NWs ensure better electronic conductance even after allowing for the low thermal loss, due mainly to the close-packed arrangements of atoms with minimum wire tension. Our first-principles quantum transport analysis further suggests that chiral Au(7,3)NWs render higher electronic conductance than chiral gold (5,3) nanotubes (NTs), once bridged by either sigma-saturated or pi-conjugated molecular moieties. It, however, turns out that asymmetricity in the characteristics of channel formation at the lead-molecule contact remains often associated with chiral Au(7,3)NWs only.
|
[
"Physics Archive->cond-mat->cond-mat.mes-hall"
] | 2018-09-05T08:31:29Z |
1708.01336
|
MemexQA: Visual Memex Question Answering
|
This paper proposes a new task, MemexQA: given a collection of photos or videos from a user, the goal is to automatically answer questions that help users recover their memory about events captured in the collection. Towards solving the task, we 1) present the MemexQA dataset, a large, realistic multimodal dataset consisting of real personal photos and crowd-sourced questions/answers, 2) propose MemexNet, a unified, end-to-end trainable network architecture for image, text and video question answering. Experimental results on the MemexQA dataset demonstrate that MemexNet outperforms strong baselines and yields the state-of-the-art on this novel and challenging task. The promising results on TextQA and VideoQA suggest MemexNet's efficacy and scalability across various QA tasks.
|
[
"Computer Science Archive->cs.CL",
"Computer Science Archive->cs.CV"
] | 2017-08-04T00:17:48Z |
2206.03551
|
NOMAD: Nonlinear Manifold Decoders for Operator Learning
|
Supervised learning in function spaces is an emerging area of machine learning research with applications to the prediction of complex physical systems such as fluid flows, solid mechanics, and climate modeling. By directly learning maps (operators) between infinite dimensional function spaces, these models are able to learn discretization invariant representations of target functions. A common approach is to represent such target functions as linear combinations of basis elements learned from data. However, there are simple scenarios where, even though the target functions form a low dimensional submanifold, a very large number of basis elements is needed for an accurate linear representation. Here we present NOMAD, a novel operator learning framework with a nonlinear decoder map capable of learning finite dimensional representations of nonlinear submanifolds in function spaces. We show this method is able to accurately learn low dimensional representations of solution manifolds to partial differential equations while outperforming linear models of larger size. Additionally, we compare to state-of-the-art operator learning methods on a complex fluid dynamics benchmark and achieve competitive performance with a significantly smaller model size and training cost.
|
[
"Computer Science Archive->cs.LG"
] | 2022-06-07T19:52:44Z |
1410.2306
|
PUMA 560 Trajectory Control Using NSGA-II Technique With Real Valued Operators
|
In the industry, Multi-objectives problems are a big defy and they are also hard to be conquered by conventional methods. For this reason, heuristic algorithms become an executable choice when facing this kind of problems.The main objective of this work is to investigate the use of the Non-dominated Sorting Genetic Algorithm II (NSGA-II) technique using the real valued recombination and the real valued mutation in the tuning of the computed torque controller gains of a PUMA560 arm manipulator. The NSGA-II algorithm with real valued operators searches for the controller gains so that the six Integral of the Absolute Errors (IAE) in joint space are minimized. The implemented model under MATLAB allows an optimization of the Proportional-Derivative computed torque controller parameters while the cost functions and time are simultaneously minimized.. Moreover, experimental results also show that the real valued recombination and the real valued mutation operators can improve the performance of NSGA-II effectively.
|
[
"Mathematics Archive->math.OC"
] | 2014-10-08T22:30:04Z |
2311.15133
|
Rotationally displaced electric field intensity distribution around square nanoantennas induced by circularly polarized light
|
An optical field around regular polygon metal nanostructures excited by circularly polarized light can exhibit rotationally displaced intensity distributions. Although this phenomenon has been recognized, its underlying mechanisms has not been sufficiently explained. Herein, finite-difference time-domain simulations and model analyses reveal that the rotationally displaced optical intensity distribution can be generated when each of the linear polarization components that constitute circular polarization excites a superposition of multiple modes. The proposed model reasonably explains the rotationally displaced patterns for a square nanoantenna and other regular-polygon nanoantennas.
|
[
"Physics Archive->physics->physics.optics"
] | 2023-11-25T22:46:57Z |
astro-ph/0202024
|
The Origin of the Correlation between the Spin Parameter and the Baryon Fraction of Galactic Disks
|
The puzzling correlation between the spin parameter lambda of galactic disks and the disk-to-halo mass fraction fdisk is investigated. We show that such a correlation arises naturally from uncertainties in determining the virial masses of dark matter halos. This result leads to the conclusion that the halo properties derived from fits to observed rotation curves are still very uncertain which might explain part of the disagreements between cosmological models and observations. We analyse lambda and fdisk as function of the adopted halo virial mass. Reasonable halo concentrations require fdisk=0.01-0.07 which is significantly smaller than the universal baryon fraction. Most of the available gas either never settled into the galactic disks or was ejected subsequently. In both cases it is not very surprising that the specific angular momentum distribution of galactic disks does not agree with the cosmological predictions which neglect these effects.
|
[
"Physics Archive->astro-ph"
] | 2002-02-01T12:39:58Z |
2205.07158
|
The Chevalley-Weil formula on nodal curves
|
In this paper, we study the eigensubspace of the space of the holomorphic differentials of nodal curves over the algebracally closed field under the action of finite automorphism groups. We compute the Chevalley- Weil formula with some additional contidions of the quotient curve and give some examples.
|
[
"Mathematics Archive->math.AG"
] | 2022-05-15T01:42:38Z |
0904.3844
|
Topological phase transition in a RNA model in the de Gennes regime
|
We study a simplified model of the RNA molecule proposed by G. Vernizzi, H. Orland and A. Zee in the regime of strong concentration of positive ions in solution. The model considers a flexible chain of equal bases that can pairwise interact with any other one along the chain, while preserving the property of saturation of the interactions. In the regime considered, we observe the emergence of a critical temperature T_c separating two phases that can be characterized by the topology of the predominant configurations: in the large temperature regime, the dominant configurations of the molecule have very large genera (of the order of the size of the molecule), corresponding to a complex topology, whereas in the opposite regime of low temperatures, the dominant configurations are simple and have the topology of a sphere. We determine that this topological phase transition is of first order and provide an analytic expression for T_c. The regime studied for this model exhibits analogies with that for the dense polymer systems studied by de Gennes
|
[
"Quantitative Biology Archive->q-bio.BM"
] | 2009-04-24T13:08:47Z |
1804.07510
|
Extending the Best Linear Approximation Framework to the Process Noise Case
|
The Best Linear Approximation (BLA) framework has already proven to be a valuable tool to analyze nonlinear systems and to start the nonlinear modeling process. The existing BLA framework is limited to systems with additive (colored) noise at the output. Such a noise framework is a simplified representation of reality. Process noise can play an important role in many real-life applications. This paper generalizes the Best Linear Approximation framework to account also for the process noise, both for the open-loop and the closed-loop setting, and shows that the most important properties of the existing BLA framework remain valid. The impact of the process noise contributions on the robust BLA estimation method is also analyzed.
|
[
"Computer Science Archive->cs.SY"
] | 2018-04-20T09:20:49Z |
1210.7998
|
Unveiling systematic biases in 1D LTE excitation-ionisation balance of Fe for FGK stars. A novel approach to determination of stellar parameters
|
We present a comprehensive analysis of different techniques available for the spectroscopic analysis of FGK stars, and provide a recommended methodology which efficiently estimates accurate stellar atmospheric parameters for large samples of stars. Our analysis includes a simultaneous equivalent width analysis of Fe I and Fe II spectral lines, and for the first time, utilises on-the-fly NLTE corrections of individual Fe I lines. We further investigate several temperature scales, finding that estimates from Balmer line measurements provide the most accurate effective temperatures at all metallicites. We apply our analysis to a large sample of both dwarf and giant stars selected from the RAVE survey. We then show that the difference between parameters determined by our method and that by standard 1D LTE excitation-ionisation balance of Fe reveals substantial systematic biases: up to 400 K in effective temperature, 1.0 dex in surface gravity, and 0.4 dex in metallicity for stars with [Fe/H] ~ -2.5. This has large implications for the study of the stellar populations in the Milky Way.
|
[
"Physics Archive->astro-ph->astro-ph.GA",
"Physics Archive->astro-ph->astro-ph.SR"
] | 2012-10-30T13:26:25Z |
2202.00627
|
Log-Concavity of Infinite Product Generating Functions
|
In the $1970$s Nicolas proved that the coefficients $p_d(n)$ defined by the generating function \begin{equation*} \sum_{n=0}^{\infty} p_d(n) \, q^n = \prod_{n=1}^{\infty} \left( 1- q^n\right)^{-n^{d-1}} \end{equation*} are log-concave for $d=1$. Recently, Ono, Pujahari, and Rolen have extended the result to $d=2$. Note that $p_1(n)=p(n)$ is the partition function and $p_2(n)=\func{pp}\left( n\right) $ is the number of plane partitions. In this paper, we invest in properties for $p_d(n)$ for general $d$. Let $n \geq 6$. Then $p_d(n)$ is almost log-concave for $n$ divisible by $3$ and almost strictly log-convex otherwise.
|
[
"Mathematics Archive->math.CO"
] | 2022-02-01T18:20:18Z |
0803.3502
|
Convergence of a finite volume scheme for nonlocal reaction-diffusion systems modelling an epidemic disease
|
We analyze a finite volume scheme for nonlocal SIR model, which is a nonlocal reaction-diffusion system modeling an epidemic disease. We establish existence solutions to the finite volume scheme, and show that it converges to a weak solution. The convergence proof is based on deriving series of a priori estimates and using a general $L^p$ compactness criterion.
|
[
"Mathematics Archive->math.NA"
] | 2008-03-25T07:49:16Z |
2312.05691
|
Improving the representation of the atmospheric boundary layer by direct assimilation of ground-based microwave radiometer observations
|
In a joint effort, MeteoSwiss and Deutscher Wetterdienst (DWD) address the need for improving the initial state of the atmospheric boundary layer (ABL) by exploiting ground-based profiling observations that aim to fill the existing observational gap in the ABL. We implemented the brightness temperature observations from ground-based microwave radiometers (MWRs) into our data assimilation systems using a local ensemble transform Kalman filter (LETKF) with RTTOV-gb (Radiative Transfer for TOVS, ground-based) as a forward operator. We were able to obtain a positive impact on the brightness temperature first guess and analysis as well as a slight impact on the ABL humidity using two MWRs at MeteoSwiss. These results led to a subsequent operational implementation of the observing system at MeteoSwiss. Furthermore, we performed an extensive set of assimilation experiments at DWD to further investigate various aspects such as the vertical localisation of selected single channels. We obtained a positive impact on the 6h-forecast of ABL temperature and humidity by assimilating two channels employing a dynamical localisation based on the sensitivity functions of RTTOV-gb but also with a static localisation in a single-channel setup. Our experiments indicate the importance of the vertical localisation when using more than one channel, although reliable improvements are challenging to obtain without a larger number of observations for both assimilation and verification.
|
[
"Physics Archive->physics->physics.ao-ph"
] | 2023-12-09T21:52:39Z |
2010.10880
|
Exploring the Universe with Dark Light Scalars
|
We study the cosmology of the dark sector consisting of (ultra) light scalars. Since the scalar mass is radiatively unstable, a special explanation is required to make the mass much smaller than the UV scale. There are two well-known mechanisms for the origin of scalar mass. The scalar can be identified as a pseudo-Goldstone boson, whose shift symmetry is explicitly broken by non-perturbative corrections, like the axion. Alternatively, it can be identified as a composite particle like the glueball, whose mass is limited by the confinement scale of the theory. In both cases, the scalar can be naturally light, but interaction behavior is quite different. The lighter the axion (glueball), the weaker (stronger) it interacts. We consider the dark axion whose shift symmetry is anomalously broken by the hidden non-abelian gauge symmetry. After the confinement of the gauge group, the dark axion and the dark glueball get masses and both form multicomponent dark matter. We carefully consider the effects of energy flow from the dark gluons to the dark axions and derive the full equations of motion for the background and the perturbed variables. The effect of the dark axion-dark gluon coupling on the evolution of the entropy and the isocurvature perturbations is also clarified. Finally, we discuss the gravo-thermal collapse of the glueball subcomponent dark matter after the halos form, in order to explore the potential to contribute to the formation of seeds for the supermassive black holes observed at high redshifts. With the simplified assumptions, the glueball subcomponent dark matter with the mass of $0.01-0.1 {\rm MeV}$, and the axion main dark matter component with the decay constant $f_a={\cal O}(10^{15}-10^{16}){\rm GeV}$, the mass of ${\cal O}(10^{-14}-10^{-18})\,{\rm eV}$, can provide the hint on the origin of the supermassive black holes at high redshifts.
|
[
"Physics Archive->astro-ph->astro-ph.CO",
"Physics Archive->hep->hep-ph"
] | 2020-10-21T10:24:23Z |
1804.09500
|
Probabilistic distillation of quantum coherence
|
The ability to distill quantum coherence is pivotal for optimizing the performance of quantum technologies; however, such a task cannot always be accomplished with certainty. Here we develop a general framework of probabilistic distillation of quantum coherence in a one-shot setting, establishing fundamental limitations for different classes of free operations. We first provide a geometric interpretation for the maximal success probability, showing that under maximally incoherent operations (MIO) and dephasing-covariant incoherent operations (DIO) the problem can be simplified into efficiently computable semidefinite programs. Exploiting these results, we find that DIO and its subset of strictly incoherent operations (SIO) have equal power in probabilistic distillation of coherence from pure input states, while MIO are strictly stronger. We then prove a fundamental no-go result: distilling coherence from any full-rank state is impossible even probabilistically. We further find that in some conditions the maximal success probability can vanish suddenly beyond a certain threshold in the distillation fidelity. Finally, we consider probabilistic coherence distillation assisted by a catalyst and demonstrate, with specific examples, its superiority to the unassisted and deterministic cases.
|
[
"Physics Archive->quant-ph"
] | 2018-04-25T12:07:50Z |
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