cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Free Energy Barriers for Crystal Nucleation from Fluid Phases
Creators: name: Koß, Peter
name: Statt, Antonia
name: Virnau, Peter
name: Binder, Kurt
Publisher: name: arXiv
Year: 2017
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: Monte Carlo simulations of crystal nuclei coexisting with the fluid phase in thermal equilibrium in finite volumes are presented and analyzed, for fluid densities from dense melts to the vapor. Generalizing the lever-rule for two-phase coexistence in the canonical ensemble to finite volume, "measurements" of the nucleus volume together with the pressure and chemical potential of the surrounding fluid allows to extract the surface free energy of the nucleus. Neither the knowledge of the (in general non-spherical) nucleus shape nor of the angle-dependent interface tension is required for this task. The feasibility of the approach is demonstrated for a variant of the Asakura-Oosawa model for colloid-polymer mixtures, which form face-centered cubic colloidal crystals. For a polymer to colloid size ratio of $0.15$, the colloid packing fraction in the fluid phase can be varied from melt values to zero by the variation of an effective attractive potential between the colloids. It is found that the approximation of spherical crystal nuclei often underestimates actual nucleation barriers significantly. Nucleation barriers are found to scale as $ΔF^*=(4π/3)^{1/3}\barγ(V^*)^{2/3}+const.$ with the nucleus volume $V^*$, and the effective surface tension $\barγ$ that accounts implicitly for the nonspherical shape can be precisely estimated.
description: 17 pages, 17 figures
Human-Robot Mutual Adaptation in Shared Autonomy
Creators: name: Nikolaidis, Stefanos
name: Zhu, Yu Xiang
name: Hsu, David
name: Srinivasa, Siddhartha
Publisher: name: arXiv
Year: 2017
Subjects: subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: Shared autonomy integrates user input with robot autonomy in order to control a robot and help the user to complete a task. Our work aims to improve the performance of such a human-robot team: the robot tries to guide the human towards an effective strategy, sometimes against the human's own preference, while still retaining his trust. We achieve this through a principled human-robot mutual adaptation formalism. We integrate a bounded-memory adaptation model of the human into a partially observable stochastic decision model, which enables the robot to adapt to an adaptable human. When the human is adaptable, the robot guides the human towards a good strategy, maybe unknown to the human in advance. When the human is stubborn and not adaptable, the robot complies with the human's preference in order to retain their trust. In the shared autonomy setting, unlike many other common human-robot collaboration settings, only the robot actions can change the physical state of the world, and the human and robot goals are not fully observable. We address these challenges and show in a human subject experiment that the proposed mutual adaptation formalism improves human-robot team performance, while retaining a high level of user trust in the robot, compared to the common approach of having the robot strictly following participants' preference.
OGLE-2014-SN-131: A long-rising Type Ibn supernova from a massive progenitor
Creators: name: Karamehmetoglu, E.
name: Taddia, F.
name: Sollerman, J.
name: Wyrzykowski, Ł.
name: Schmidl, S.
name: Fraser, M.
name: Fremling, C.
name: Greiner, J.
name: Inserra, C.
name: Kostrzewa-Rutkowska, Z.
name: Maguire, K.
name: Smartt, S.
name: Sullivan, M.
name: Young, D. R.
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Type Ibn supernovae (SNe Ibn) are thought to be the core-collapse explosions of massive stars whose ejecta interact with He-rich circumstellar material (CSM). We report the discovery of a SN Ibn, with the longest rise-time ever observed, OGLE-2014-SN-131. We discuss the potential powering mechanisms and the progenitor nature of this peculiar stripped-envelope (SE), circumstellar-interacting SN. Optical photometry and spectroscopy were obtained with multiple telescopes including VLT, NTT, and GROND. We compare light curves and spectra with those of other known SNe Ibn and Ibc. CSM velocities are derived from the spectral analysis. The SN light curve is modeled under different assumptions about its powering mechanism (${^{56}}$Ni decay, CSM-interaction, magnetar) in order to estimate the SN progenitor parameters. OGLE-2014-SN-131 spectroscopically resembles SNe Ibn such as SN 2010al. Its peak luminosity and post-peak colors are also similar to those of other SNe Ibn. However, it shows an unprecedentedly long rise-time and a much broader light curve compared to other SNe Ibn. Its bolometric light curve can be reproduced by magnetar and CSM-interaction models, but not by a ${^{56}}$Ni-decay powering model. To explain the unusually long rise-time, the broad light curve, the light curve decline, and the spectra characterized by narrow emission lines, we favor a powering mechanism where the SN ejecta are interacting with a dense CSM. The progenitor of OGLE-2014-SN-131 was likely a Wolf-Rayet star with a mass greater than that of a typical SN Ibn progenitor, which expelled the CSM that the SN is interacting with.
description: 14 pages, 11 Figures. Accepted for publication in A&A
Specific features and symmetries for magnetic and chiral bands in nuclei
Creators: name: Raduta, A. A.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: Magnetic and chiral bands have been a hot subject for more than twenty years. Therefore, quite large volumes of experimental data as well as theoretical descriptions have been accumulated. Although some of the formalisms are not so easy to handle, the results agree impressively well with the data. The objective of this paper is to review the actual status of both experimental and theoretical investigations. Aiming at making this material accessible to a large variety of readers, including young students and researchers, I gave some details on the schematic models which are able to unveil the main features of chirality in nuclei. Also, since most formalisms use a rigid triaxial rotor for the nuclear system's core, I devoted some space to the semi-classical description of the rigid triaxial as well as of the tilted triaxial rotor. In order to answer the question whether the chiral phenomenon is spread over the whole nuclear chart and whether it is specific only to a certain type of nuclei, odd-odd, odd-even or even-even, the current results in the mass regions of $A\sim 60,80,100,130,180,200$ are briefly described for all kinds of odd/even-odd/even systems. The chiral geometry is a sufficient condition for a system of proton-particle, neutron-hole and a triaxial rotor to have the electromagnetic properties of chiral bands. In order to prove that such geometry is not unique for generating magnetic bands with chiral features, I presented a mechanism for a new type of chiral bands. One tries to underline the fact that this rapidly developing field is very successful in pushing forward nuclear structure studies.
description: 80 pages, 22 figures
Nonparametric estimation of conditional value-at-risk and expected shortfall based on extreme value theory
Creators: name: Martins-Filho, Carlos
name: Yao, Feng
name: Torero, Maximo
Publisher: name: arXiv
Year: 2016
Subjects: subject: Methodology (stat.ME)
subject: FOS: Computer and information sciences
subject: 62G32, 62G07, 62G08, 62G20

description: We propose nonparametric estimators for conditional value-at-risk (CVaR) and conditional expected shortfall (CES) associated with conditional distributions of a series of returns on a financial asset. The return series and the conditioning covariates, which may include lagged returns and other exogenous variables, are assumed to be strong mixing and follow a nonparametric conditional location-scale model. First stage nonparametric estimators for location and scale are combined with a generalized Pareto approximation for distribution tails proposed by Pickands (1975) to give final estimators for CVaR and CES. We provide consistency and asymptotic normality of the proposed estimators under suitable normalization. We also present the results of a Monte Carlo study that sheds light on their finite sample performance. Empirical viability of the model and estimators is investigated through a backtesting exercise using returns on future contracts for five agricultural commodities.
description: 45 pages, Econometric Theory, 2017
Relative orbit orientation in several resolved multiple systems
Creators: name: Tokovinin, Andrei
name: Latham, David W.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: This work extends the still modest number of multiple stars with known relative orbit orientation. Accurate astrometry and radial velocities are used jointly to compute or update outer and inner orbits in three nearby triple systems HIP 101955 (orbital periods 38.68 and 2.51 years), HIP 103987 (19.20 and 1.035 years), HIP 111805 (30.13 and 1.50 years) and in one quadruple system HIP 2643 (periods 70.3, 4.85 and 0.276 years), all composed of solar-type stars. The masses are estimated from the absolute magnitudes and checked using the orbits. The ratios of outer to inner periods (from 14 to 20) and the eccentricities of the outer orbits are moderate. These systems are dynamically stable, but not very far from the stability limit. In three systems all orbits are approximately coplanar and have small eccentricity, while in HIP 101955 the inner orbit with e=0.6 is highly inclined.
description: Accepted by ApJ. 10 pages, 12 figures, 6 tables
Hamiltonian analysis of the cuscuton
Creators: name: Gomes, Henrique
name: Guariento, Daniel C.
Publisher: name: arXiv
Year: 2017
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: The cuscuton was introduced in the context of cosmology as a field with infinite speed of propagation. It has been claimed to resemble Hořava gravity in a certain limit, and it is a good candidate for an ether theory in which a time-dependent cosmological constant appears naturally. The analysis of its properties is usually performed in the Lagrangian framework, which makes issues like the counting of its dynamical degrees of freedom less clear-cut. Here we perform a Hamiltonian analysis of the theory. We show that the homogeneous limit with local degrees of freedom has singular behavior in the Hamiltonian framework. In other frames, it has an extra scalar degree of freedom. The homogeneous field has regular behavior only if defined a priori as a spatially constant field in a CMC foliation and contributing with a single global degree of freedom. Lastly, we find conditions on the cuscuton potential for the resulting lapse function to be non-zero throughout evolution.
description: 10 pages
CO excitation in the Seyfert galaxy NGC7130
Creators: name: Pozzi, F.
name: Vallini, L.
name: Vignali, C.
name: Talia, M.
name: Gruppioni, C.
name: Mingozzi, M.
name: Massardi, M.
name: Andreani, P.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present a coherent multi-band modelling of the CO Spectral Energy Distribution of the local Seyfert Galaxy NGC7130 to assess the impact of the AGN activity on the molecular gas. We take advantage of all the available data from X-ray to the sub-mm, including ALMA data. The high-resolution (~0.2") ALMA CO(6-5) data constrain the spatial extension of the CO emission down to ~70 pc scale. From the analysis of the archival CHANDRA and NuSTAR data, we infer the presence of a buried, Compton-thick AGN of moderate luminosity, L_2-10keV ~ 1.6x10^{43} ergs-1. We explore photodissociation and X-ray-dominated regions (PDRs and XDRs) models to reproduce the CO emission. We find that PDRs can reproduce the CO lines up to J~6, however, the higher rotational ladder requires the presence of a separate source of excitation. We consider X-ray heating by the AGN as a source of excitation, and find that it can reproduce the observed CO Spectral Energy Distribution. By adopting a composite PDR+XDR model, we derive molecular cloud properties. Our study clearly indicates the capabilities offered by current-generation of instruments to shed light on the properties of nearby galaxies adopting state-of-the art physical modelling.
description: 5 pages, 3 figures, accepted for publication in MNRAS Letters
On the gauge chosen by the bosonic open string
Creators: name: Pesando, Igor
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: String theory gives S matrix elements om which is not possible to read any gauge information. Using factorization we go off shell in the simplest and most naive way and we read which are the vertices suggested by string. To compare with the associated Effective Field Theory it is natural to use color ordered vertices. The alpha'=0 color ordered vertices suggested by string theory are more efficient than the usual ones since the three gluon color ordered vertex has three terms instead of six and the four gluon one has one term instead of three. They are written in the so called Gervais-Neveu gauge. The full Effective Field Theory is in a generalization of the Gervais-Neveu gauge with alpha') corrections. Moreover a field redefinition is required to be mapped to the field used by string theory. We also give an intuitive way of understanding why string choose this gauge in terms of the minimal number of couplings necessary to reproduce the non abelian amplitudes starting from color ordered ones.
description: 37 pages, 9 figures
Virtual Resonant Emission and Oscillatory Long-Range Tails in van der Waals Interactions of Excited States: QED Treatment and Applications
Creators: name: Jentschura, U. D.
name: Adhikari, C. M.
name: Debierre, V.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We report on a quantum electrodynamic (QED) investigation of the interaction between a ground state atom with another atom in an excited state. General expressions, applicable to any atom, are indicated for the long-range tails which are due to virtual resonant emission and absorption into and from vacuum modes whose frequency equals the transition frequency to available lower-lying atomic states. For identical atoms, one of which is in an excited state, we also discuss the mixing term which depends on the symmetry of the two-atom wave function (these evolve into either the gerade or the ungerade state for close approach), and we include all nonresonant states in our rigorous QED treatment. In order to illustrate the findings, we analyze the fine-structure resolved van der Waals interaction for nD-1S hydrogen interactions with n=8,10,12 and find surprisingly large numerical coefficients.
description: 6 pages; RevTeX
CHAOS: A Parallelization Scheme for Training Convolutional Neural Networks on Intel Xeon Phi
Creators: name: Viebke, Andre
name: Memeti, Suejb
name: Pllana, Sabri
name: Abraham, Ajith
Publisher: name: arXiv
Year: 2017
Subjects: subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Deep learning is an important component of big-data analytic tools and intelligent applications, such as, self-driving cars, computer vision, speech recognition, or precision medicine. However, the training process is computationally intensive, and often requires a large amount of time if performed sequentially. Modern parallel computing systems provide the capability to reduce the required training time of deep neural networks. In this paper, we present our parallelization scheme for training convolutional neural networks (CNN) named Controlled Hogwild with Arbitrary Order of Synchronization (CHAOS). Major features of CHAOS include the support for thread and vector parallelism, non-instant updates of weight parameters during back-propagation without a significant delay, and implicit synchronization in arbitrary order. CHAOS is tailored for parallel computing systems that are accelerated with the Intel Xeon Phi. We evaluate our parallelization approach empirically using measurement techniques and performance modeling for various numbers of threads and CNN architectures. Experimental results for the MNIST dataset of handwritten digits using the total number of threads on the Xeon Phi show speedups of up to 103x compared to the execution on one thread of the Xeon Phi, 14x compared to the sequential execution on Intel Xeon E5, and 58x compared to the sequential execution on Intel Core i5.
description: The Journal of Supercomputing, 2017
A comparative study of resists and lithographic tools using the Lumped Parameter Model
Creators: name: Fallica, Roberto
name: Kirchner, Robert
name: Mailly, Dominique
name: Ekinci, Yasin
Publisher: name: arXiv
Year: 2017
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: A comparison of the performance of high resolution lithographic tools is presented here. We use extreme ultraviolet interference lithography, electron beam lithography, and He ion beam lithography tools on two different resists that are processed under the same conditions. The dose-to-clear and the lithographic contrast are determined experimentally and are used to compare the relative efficiency of each tool. The results are compared to previous studies and interpreted in the light of each tool-specific secondary electron yield. In addition, the patterning performance is studied by exposing dense line/spaces patterns and the relation between critical dimension and exposure dose is discussed. Finally, the Lumped Parameter Model is employed in order to quantitatively estimate the critical dimension of line/spaces, using each tool specific aerial image. Our implementation is then validated by fitting the model to the experimental data from interference lithography exposures, and extracting the resist contrast.
description: EIPBN 2016 Conference
Stellar origin of 15N-rich presolar SiC grains of type AB: supernovae with explosive hydrogen burning
Creators: name: Liu, Nan
name: Nittler, Larry R.
name: Pignatari, Marco
name: Alexander, Conel M. O'D.
name: Wang, Jianhua
Publisher: name: arXiv
Year: 2017
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We report C, N, and Si isotopic data for 59 highly 13C-enriched presolar submicron- to micron-sized SiC grains from the Murchison meteorite, including eight putative nova grains (PNGs) and 29 15N-rich (14N/15N<=solar) AB grains, and their Mg-Al, S, and Ca-Ti isotope data when available. These 37 grains are enriched in 13C, 15N and 26Al with the PNGs showing more extreme enhancements. The 15N-rich AB grains show systematically higher 26Al and 30Si excesses than the 14N-rich AB grains. Thus, we propose to divide the AB grains into groups 1 (14N/15N=solar). For the first time, we have obtained both S and Ti isotopic data for five AB1 grains and one PNG, and found 32S and/or 50Ti enhancements. Interestingly, one AB1 grain had the largest 32S and 50Ti excesses, strongly suggesting a neutron-capture nucleosynthetic origin of the 32S excess and thus the initial presence of radiogenic 32Si (t1/2=153 yr). More importantly, we found that the 15N and 26Al excesses of AB1 grains form a trend that extends to the region in the N-Al isotope plot occupied by C2 grains, strongly indicating a common stellar origin for both AB1 and C2 grains. Comparison of supernova models with the AB1 and C2 grain data indicates that these grains came from SNe that experienced H ingestion into the He/C zones of their progenitors.
Optical hyperpolarization of nitrogen donor spins in bulk diamond
Creators: name: Loretz, M.
name: Takahashi, H.
name: Segawa, T. F.
name: Boss, J. M.
name: Degen, C. L.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We report hyperpolarization of the electronic spins associated with substitutional nitrogen defects in bulk diamond crystal. Hyperpolarization is achieved by optical pumping of nitrogen vacancy centers followed by rapid cross relaxation at the energy level matching condition in a 51 mT bias field. The maximum observed donor spin polarization is 0.9 \% corresponding to an enhancement by 25 compared to the thermal Boltzmann polarization. A further accumulation of polarization is impeded by an anomalous optical saturation effect that we attribute to charge state conversion processes. Hyperpolarized nitrogen donors may form a useful resource for increasing the efficiency of diamond-based dynamic nuclear polarization devices.
description: 15 pages, 4 figures
MPEC 2023-R91 : 2023 RR2
Creators: name: Minor Planet Center Staff
Publisher: name: The Minor Planet Center
Year: 2023
Subjects: subject: Small Solar System bodies
valueUri: http://astrothesaurus.org/uat/1469
subject: 2023 RR2

description: The Minor Planet Electronic Circulars contain information on unusual minor planets, routine data on comets and natural satellites, and occasional editorial announcements.  They are published on behalf of Division F of the International Astronomical Union by the Minor Planet Center, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Internal rotation of 13 low-mass low-luminosity red giants in the Kepler field
Creators: name: Triana, Santiago Andrés
name: Corsaro, Enrico
name: De Ridder, Joris
name: Bonanno, Alfio
name: Hernández, Fernando Pérez
name: García, Rafael
Publisher: name: arXiv
Year: 2017
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The Kepler space telescope has provided time series of red giants of such unprecedented quality that a detailed asteroseismic analysis becomes possible. For a limited set of about a dozen red giants, the observed oscillation frequencies obtained by peak-bagging together with the most recent pulsation codes allowed us to reliably determine the core/envelope rotation ratio. The results so far show that the current models are unable to reproduce the rotation ratios, predicting higher values than what is observed and thus indicating that an efficient angular momentum transport mechanism should be at work. Here we provide an asteroseismic analysis of a sample of 13 low-luminosity low-mass red giant stars observed by Kepler during its first nominal mission. These targets form a subsample of the 19 red giants studied previously Corsaro et al. 2015, which not only have a large number of extracted oscillation frequencies, but also unambiguous mode identifications We aim to extend the sample of red giants for which internal rotation ratios obtained by theoretical modeling of peak-bagged frequencies are available. We also derive the rotation ratios using different methods, and compare the results of these methods with each other. We built seismic models using a grid search combined with a Nelder-Mead simplex algorithm and obtained rotation averages employing Bayesian inference and inversion methods. We compared these averages with those obtained using a previously developed model-independent method. We find that the cores of the red giants in this sample are rotating 5 to 10 times faster than their envelopes, which is consistent with earlier results. The rotation rates computed from the different methods show good agreement for some targets, while some discrepancies exist for others.
description: 15 pages, 16 figures, accepted for publication in Astronomy and Astrophysics
3D spatially-resolved optical energy density enhanced by wavefront shaping
Creators: name: Hong, Peilong
name: Ojambati, Oluwafemi S.
name: Lagendijk, Ad
name: Mosk, Allard P.
name: Vos, Willem L.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Optics (physics.optics)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Biological Physics (physics.bio-ph)
subject: FOS: Physical sciences

description: We study the three-dimensional (3D) spatially-resolved distribution of the energy density of light in a 3D scattering medium upon the excitation of open transmission channels. The open transmission channels are excited by spatially shaping the incident optical wavefronts. To probe the local energy density, we excite isolated fluorescent nanospheres distributed inside the medium. From the spatial fluorescent intensity pattern we obtain the position of each nanosphere, while the total fluorescent intensity gauges the energy density. Our 3D spatially-resolved measurements reveal that the local energy density versus depth (z) is enhanced up to 26X at the back surface of the medium, while it strongly depends on the transverse (x; y) position. We successfully interpret our results with a newly developed 3D model that considers the time-reversed diffusion starting from a point source at the back surface. Our results are relevant for white LEDs, random lasers, solar cells, and biomedical optics.
Characterization of the quantum phase transition in a two-mode Dicke model for different cooperation numbers
Creators: name: Quezada, L. F.
name: Nahmad-Achar, E.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We show how the use of variational states to approximate the ground state of a system can be employed to study a multi-mode Dicke model. One of the main contributions of this work is the introduction of a not very commonly used quantity, the cooperation number, and the study of its influence on the behavior of the system, paying particular attention to the quantum phase transitions and the accuracy of the used approximations. We also show how these phase transitions affect the dependence of the expectation values of some of the observables relevant to the system and the entropy of entanglement with respect to the energy difference between atomic states and the coupling strength between matter and radiation, thus characterizing the transitions in different ways.
description: 10 pages, 16 figures
The natural algorithmic approach of mixed trigonometric-polynomial problems
Creators: name: Lutovac, Tatjana
name: Malesevic, Branko
name: Mortici, Cristinel
Publisher: name: arXiv
Year: 2017
Subjects: subject: Classical Analysis and ODEs (math.CA)
subject: Symbolic Computation (cs.SC)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences
subject: 41A10, 26D05, 12L05, 41A58

description: The aim of this paper is to present a new algorithm for proving mixed trigonometric-polynomial inequalities by reducing to polynomial inequalities. Finally, we show the great applicability of this algorithm and as examples, we use it to analyze some new rational (Pade) approximations of the function $\cos^2(x)$, and to improve a class of inequalities by Z.-H. Yang. The results of our analysis could be implemented by means of an automated proof assistant, so our work is a contribution to the library of automatic support tools for proving various analytic inequalities.
The Dark Components of the Universe Are Slowly Clarified
Creators: name: Burdyuzha, Vladimir
Publisher: name: arXiv
Year: 2017
Subjects: subject: General Physics (physics.gen-ph)
subject: FOS: Physical sciences

description: The dark sector of the Universe is beginning to be clarified step by step. If the dark energy is vacuum energy, then 123 orders are exactly reduced by ordinary physical processes. For many years these unexplained orders were called a crisis in physics. There was indeed a "crisis" before the introduction of the holographic principle and entropic force in physics. The vacuum energy was spent for the organization of new microstates during the entire life of the Universe, but in the initial period of its evolution the vacuum energy (78 orders) were reduced more effectively by the vacuum condensates produced by phase transitions, because the Universe lost the high symmetry during its expansion. Important problems of physics and cosmology can be solved if the quarks, leptons, and gauge bosons are composite particles. The dark matter, partially or all consisting of familon-type pseudo-Goldstone bosons with a mass of 10^{-5} - 10^{-3} eV, can be explained in the composite model. Three generations of elementary particles are absolutely necessary in this model. In addition, this model realizes three relativistic phase transitions in a medium of familons at different red shifts, forming a large-scale structure of dark matter that was "repeated" by baryons. We predict the detection of dark matter dynamics, the detection of familons as dark matter particles, and the development of spectroscopy for dark medium due to the probable presence of dark atoms in it. Other viewpoints on the dark components of the Universe are also discussed briefly.
description: 34 pages, 0 figures
Large gravitons and near-horizon diffeomorphisms
Creators: name: da Cunha, Bruno Carneiro
name: Rudrigues, Filipe
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Usual gauge fixing procedures in classical general relativity rely on the existence of solutions of a second order wave equation. We propose to use the equation to relate asymptotic symmetries at infinity to asymptotic symmetries of a black hole horizon, in tune with recent proposals. We illustrate the construction for the BTZ and four-dimensional Kerr black holes. We find in both cases a realization of the group of diffeomorphisms of the circle $S^1$.
description: JHEP3 style, 27 pages, 2 figures, References added, typos corrected
Rician MIMO Channel- and Jamming-Aware Decision Fusion
Creators: name: Ciuonzo, D.
name: Aubry, A.
name: Carotenuto, V.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: In this manuscript we study channel-aware decision fusion (DF) in a wireless sensor network (WSN) where: (i) the sensors transmit their decisions simultaneously for spectral efficiency purposes and the DF center (DFC) is equipped with multiple antennas; (ii) each sensor-DFC channel is described via a Rician model. As opposed to the existing literature, in order to account for stringent energy constraints in the WSN, only statistical channel information is assumed for the non-line-of sight (scattered) fading terms. For such a scenario, sub-optimal fusion rules are developed in order to deal with the exponential complexity of the likelihood ratio test (LRT) and impractical (complete) system knowledge. Furthermore, the considered model is extended to the case of (partially unknown) jamming-originated interference. Then the obtained fusion rules are modified with the use of composite hypothesis testing framework and generalized LRT. Coincidence and statistical equivalence among them are also investigated under some relevant simplified scenarios. Numerical results compare the proposed rules and highlight their jammingsuppression capability.
description: Accepted in IEEE Transactions on Signal Processing 2017
Bulk crystalline optomechanics
Creators: name: Renninger, W. H.
name: Kharel, P.
name: Behunin, R. O.
name: Rakich, P. T.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Brillouin processes couple light and sound through optomechanical three-wave interactions. Within bulk solids, this coupling is mediated by the intrinsic photo-elastic material response yielding coherent emission of high frequency (GHz) acoustic phonons. This same interaction produces strong optical nonlinearities that overtake both Raman or Kerr nonlinearities in practically all solids. In this paper, we show that the strength and character of Brillouin interactions are radically altered at low temperatures when the phonon coherence length surpasses the system size. In this limit, the solid becomes a coherent optomechanical system with macroscopic (cm-scale) phonon modes possessing large ($60\ μ\rm{g}$) motional masses. These phonon modes, which are formed by shaping the surfaces of the crystal into a confocal phononic resonator, yield appreciable optomechanical coupling rates (${\sim}100$ Hz), providing access to ultra-high $Q$-factor ($4.2{\times}10^7$) phonon modes at high ($12$ GHz) carrier frequencies. The single-pass nonlinear optical susceptibility is enhanced from its room temperature value by more than four orders of magnitude. Through use of bulk properties, rather than nano-structural control, this comparatively simple approach is enticing for the ability to engineer optomechanical coupling at high frequencies and with high power handling. In contrast to cavity optomechanics, we show that this system yields a unique form of dispersive symmetry breaking that enables selective phonon heating or cooling without an optical cavity (i.e., cavity-less optomechanics). Extending these results, practically any transparent crystalline material can be shaped into an optomechanical system as the basis for materials spectroscopy, new regimes of laser physics, precision metrology, quantum information processing, and for studies of macroscopic quantum coherence.
Structure of $^{20}$Ne states in the resonance $^{16}$O+$α$ elastic scattering
Creators: name: Nauruzbayev, D. K.
name: Goldberg, V. Z.
name: Nurmukhanbetova, A. K.
name: Golovkov, M. S.
name: Volya, A.
name: Rogachev, G. V.
name: Tribble, R. E.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: Nuclear Theory (nucl-th)
subject: Accelerator Physics (physics.acc-ph)
subject: FOS: Physical sciences

description: Background The nuclear structure of the cluster bands in $^{20}$Ne presents a challenge for different theoretical approaches. It is especially difficult to explain the broad 0$^+$, 2$^+$ states at 9 MeV excitation energy. Simultaneously, it is important to obtain more reliable experimental data for these levels in order to quantitatively assess the theoretical framework. Purpose To obtain new data on $^{20}$Ne $α$ cluster structure. Method Thick target inverse kinematics technique was used to study the $^{16}$O+$α$ resonance elastic scattering and the data were analyzed using an \textit{R} matrix approach. The $^{20}$Ne spectrum, the cluster and nucleon spectroscopic factors were calculated using cluster-nucleon configuration interaction model (CNCIM). Results We determined the parameters of the broad resonances in \textsuperscript{20}Ne: 0$^+$ level at 8.77 $\pm$ 0.150 MeV with a width of 750 (+500/-220) keV; 2$^+$ level at 8.75 $\pm$ 0.100 MeV with the width of 695 $\pm$ 120 keV; the width of 9.48 MeV level of 65 $\pm$ 20 keV and showed that 9.19 MeV, 2$^+$ level (if exists) should have width $\leq$ 10 keV. The detailed comparison of the theoretical CNCIM predictions with the experimental data on cluster states was made. Conclusions Our experimental results by the TTIK method generally confirm the adopted data on $α$ cluster levels in $^{20}$Ne. The CNCIM gives a good description of the $^{20}$Ne positive parity states up to an excitation energy of $\sim$ 7 MeV, predicting reasonably well the excitation energy of the states and their cluster and single particle properties. At higher excitations, the qualitative disagreement with the experimentally observed structure is evident, especially for broad resonances.
Absorption Spectrum of a Two-Level System Subjected to a Periodic Pulse Sequence
Creators: name: Fotso, H. F.
name: Dobrovitski, V. V.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We investigate how the quantum control of a two-level system (TLS) coupled to photons can modify and tune the TLS's photon absorption spectrum. Tuning and controlling the emission and the absorption is of much interest e.g.\ for the development of efficient interfaces between stationary and flying qubits in modern architectures for quantum computation and quantum communication. We consider the periodic pulse control, where the TLS is subjected to a periodic sequence of the near-resonant Rabi driving pulses, each pulse implementing a 180$^\circ$ rotation. For small inter-pulse delays, the absorption spectrum features a pronounced peak of stimulated emission at the pulse frequency, as well as equidistant satellite peaks with smaller spectral weights. As long as the detuning between the carrier frequency of the driving and the TLS transition frequency remains moderate, this spectral shape shows little change. Therefore, the quantum control allows shifting the absorption peak to a desired position, and locks the absorption peak to the carrier frequency of the driving pulses. Detailed description of the spectrum, and its evolution as a function time, the inter-pulse spacing and the detuning, is presented.
description: 13 pages, 7 figures
Experimental determination of phonon thermal conductivity and Lorenz ratio of single crystal metals: Al, Cu and Zn
Creators: name: Yao, Mengliang
name: Zebarjadi, Mona
name: Opeil, Cyril P.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We use a magnetothermal resistance method to measure lattice thermal conductivity of pure single crystal metals over a wide range of temperatures. Large transverse magnetic fields are applied to suppress electronic thermal conduction. The total thermal conductivity and the electrical conductivity are measured as functions of applied magnetic field. The lattice thermal conductivity is then extracted by extrapolating the thermal conductivity versus electrical conductivity curve at zero electrical conductivity. We used this method to experimentally measure the lattice thermal conductivity and Lorenz number in single crystal Al (100), Cu (100) and Zn (001) in a temperature range of 5 to 60 K. Our results show that the measured phonon thermal conductivity versus temperature plot has a peak around one tenth of the Debye Temperature, and the Lorenz number is found to deviate from the Sommerfeld value in the intermediate temperature range.
description: 12 pages, 10 figures, original research manuscript
The effect of Chern-Simons dynamics on the energy of electrically charged and spinning vortices
Creators: name: Navarro-Lerida, Francisco
name: Radu, Eugen
name: Tchrakian, D. H.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study the effect of a Chern-Simons term on the electrically charged and spinning solitons of several $U(1)$ gauged models in $2+1$ dimensions. These are vortices of complex scalar field theories, both with and without symmetry breaking dynamics, and the $O(3)$ Skyrme model. In all cases the gauge decoupling limits are also considered. It is well known that the effect of the Chern-Simons dynamics is to endow vortices with electric charge $Q_e$ and spin $J$, but our main aim here is to reveal a new feature: that the mass-energy $E$ of the electrically charged vortex can be lower than that of the electrically neutral one, in contrast to the usual monotonic increase of $E$ with $Q_e$. These effects of Chern-Simons dynamics were observed previously in $3+1$ dimensional systems, and the present results can be viewed as corroborating the latter. Moreover, the usual energy-spin relationship is likewise altered. We carry out a detailed quantitative analysis of azimuthally symmetric vortices and describe their qualitative features by constructing the solutions numerically.
description: 29 pages, 9 figures
Sparsity constrained split feasibility for dose-volume constraints in inverse planning of intensity-modulated photon or proton therapy
Creators: name: Penfold, S.
name: Zalas, R.
name: Casiraghi, M.
name: Brooke, M.
name: Censor, Y.
name: Schulte, R.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Medical Physics (physics.med-ph)
subject: Optimization and Control (math.OC)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: A split feasibility formulation for the inverse problem of intensity-modulated radiation therapy (IMRT) treatment planning with dose-volume constraints (DVCs) included in the planning algorithm is presented. It involves a new type of sparsity constraint that enables the inclusion of a percentage-violation constraint in the model problem and its handling by continuous (as opposed to integer) methods. We propose an iterative algorithmic framework for solving such a problem by applying the feasibility-seeking CQ-algorithm of Byrne combined with the automatic relaxation method (ARM) that uses cyclic projections. Detailed implementation instructions are furnished. Functionality of the algorithm was demonstrated through the creation of an intensity-modulated proton therapy plan for a simple 2D C-shaped geometry and also for a realistic base-of-skull chordoma treatment site. Monte Carlo simulations of proton pencil beams of varying energy were conducted to obtain dose distributions for the 2D test case. A research release of the Pinnacle3 proton treatment planning system was used to extract pencil beam doses for a clinical base-of-skull chordoma case. In both cases the beamlet doses were calculated to satisfy dose-volume constraints according to our new algorithm. Examination of the dose-volume histograms following inverse planning with our algorithm demonstrated that it performed as intended. The application of our proposed algorithm to dose-volume constraint inverse planning was successfully demonstrated. Comparison with optimized dose distributions from the research release of the Pinnacle3 treatment planning system showed the algorithm could achieve equivalent or superior results.
description: Technical report, July 10, 2016; Revised January 10, 2017. Physics in Medicine and Biology, accepted for publication
Proximity Eliashberg theory of electrostatic field-effect-doping in superconducting films
Creators: name: Ummarino, G. A.
name: Piatti, E.
name: Daghero, D.
name: Gonnelli, R. S.
name: Sklyadneva, Irina Yu.
name: Chulkov, E. V.
name: Heid, R.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We calculate the effect of a static electric field on the critical temperature of a s-wave one band superconductor in the framework of proximity effect Eliashberg theory. In the weak electrostatic field limit the theory has no free parameters while, in general, the only free parameter is the thickness of the surface layer where the electric field acts. We conclude that the best situation for increasing the critical temperature is to have a very thin film of a superconducting material with a strong increase of electron-phonon (boson) constant upon charging.
description: 9 pages, 5 figures
Recurrences in an isolated quantum many-body system
Creators: name: Rauer, Bernhard
name: Erne, Sebastian
name: Schweigler, Thomas
name: Cataldini, Federica
name: Tajik, Mohammadamin
name: Schmiedmayer, Jörg
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Even though the evolution of an isolated quantum system is unitary, the complexity of interacting many-body systems prevents the observation of recurrences of quantum states for all but the smallest systems. For large systems one can not access the full complexity of the quantum states and the requirements to observe a recurrence in experiments reduces to being close to the initial state with respect to the employed observable. Selecting an observable connected to the collective excitations in one-dimensional superfluids, we demonstrate recurrences of coherence and long range order in an interacting quantum many-body system containing thousands of particles. This opens up a new window into the dynamics of large quantum systems even after they reached a transient thermal-like state.
description: 5 pages, 4 figures + supplementary materials (9 pages, 6 figures)
The prevalence of chaotic dynamics in games with many players
Creators: name: Sanders, James B. T.
name: Farmer, J. Doyne
name: Galla, Tobias
Publisher: name: arXiv
Year: 2016
Subjects: subject: General Economics (econ.GN)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Chaotic Dynamics (nlin.CD)
subject: Physics and Society (physics.soc-ph)
subject: FOS: Economics and business
subject: FOS: Physical sciences

description: We study adaptive learning in a typical p-player game. The payoffs of the games are randomly generated and then held fixed. The strategies of the players evolve through time as the players learn. The trajectories in the strategy space display a range of qualitatively different behaviors, with attractors that include unique fixed points, multiple fixed points, limit cycles and chaos. In the limit where the game is complicated, in the sense that the players can take many possible actions, we use a generating-functional approach to establish the parameter range in which learning dynamics converge to a stable fixed point. The size of this region goes to zero as the number of players goes to infinity, suggesting that complex non-equilibrium behavior, exemplified by chaos, may be the norm for complicated games with many players.
description: 21 pages, 11 figures
Beyond WYSIWYG: Sharing Contextual Sensing Data Through mmWave V2V Communications
Creators: name: Perfecto, Cristina
name: Del Ser, Javier
name: Bennis, Mehdi
name: Bilbao, Miren Nekane
Publisher: name: arXiv
Year: 2017
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: In vehicular scenarios context awareness is a key enabler for road safety. However, the amount of contextual information that can be collected by a vehicle is stringently limited by the sensor technology itself (e.g., line-of-sight, coverage, weather robustness) and by the low bandwidths offered by current wireless vehicular technologies such as DSRC/802.11p. Motivated by the upsurge of research around millimeter-wave vehicle-to-anything (V2X) communications, in this work we propose a distributed vehicle-to-vehicle (V2V) association scheme that considers a quantitative measure of the potential value of the shared contextual information in the pairing process. First, we properly define the utility function of every vehicle balancing classical channel state and queuing state information (CSI/QSI) with context information i.e., sensing content resolution, timeliness and enhanced range of the sensing. Next we solve the problem via a distributed many-to-one matching game in a junction scenario with realistic vehicular mobility traces. It is shown that when receivers are able to leverage information from different sources, the average volume of collected extended sensed information under our proposed scheme is up to 71% more than that of distance and minimum delay-based matching baselines.
description: 6 pages, 4 figures, Accepted in EuCNC 2017, Oulu, Finland, June 12-15, 2017