cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
The role of quantum measurement in stochastic thermodynamics
Creators: name: Elouard, Cyril
name: Herrera-Martí, David
name: Clusel, Maxime
name: Auffèves, Alexia
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: This article sets up a new formalism to investigate stochastic thermodynamics in the quantum regime, where stochasticity and irreversibility primarily come from quantum measurement. In the absence of any bath, we define a purely quantum component to heat exchange, that corresponds to energy fluctuations caused by measurement back-action. Energetic and entropic signatures of measurement induced irreversibility are then investigated for canonical experiments of quantum optics, and the energetic cost of counter-acting decoherence is characterized on a simple state-stabilizing protocol. By placing quantum measurement in a central position, our formalism contributes to bridge a gap between experimental quantum optics and quantum thermodynamics.
$A_4$ and CP symmetry and a model with maximal CP violation
Creators: name: Li, Cai-Chang
name: Lu, Jun-Nan
name: Ding, Gui-Jun
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study a second CP symmetry compatible with the $A_4$ flavor group, which interchanges the representations $\mathbf{1}'$ and $\mathbf{1}"$. We analyze the lepton mixing patterns arising from the $A_4$ and CP symmetry broken to residual subgroups $Z_3$ and $Z_2\times CP$ in the charged lepton and neutrino sectors respectively. One phenomenologically viable mixing pattern is found, and it predicts maximal atmospheric mixing angle as well as maximal Dirac CP phase, trivial Majorana phase and the correlation $\sin^2θ_{12}\cos^2θ_{13}=1/3$. We construct a concrete model based on the $A_4$ and CP symmetry, the above interesting mixing pattern is achieved, the observed charged lepton mass hierarchy is reproduced, and the reactor mixing angle $θ_{13}$ is of the correct order.
description: 22 pages, 1 figure
A Cross-correlation Study between IceCube Neutrino Events and the Fermi Unresolved Gamma-ray Sky
Creators: name: Negro, Michela
name: Crnogorčević, Milena
name: Burns, Eric
name: Charles, Eric
name: Marcotulli, Lea
name: Caputo, Regina
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: With the coincident detections of electromagnetic radiation together with gravitational waves (GW170817) or neutrinos (TXS 0506+056), the new era of multimessenger astrophysics has begun. Of particular interest are the searches for correlation between the high-energy astrophysical neutrinos detected by the IceCube Observatory and gamma-ray photons detected by the Fermi Large Area Telescope (LAT). So far, only sources detected by the LAT have been considered in correlation with IceCube neutrinos, neglecting any emission from sources too faint to be resolved individually. Here, we present the first cross-correlation analysis considering the unresolved gamma-ray background (UGRB) and IceCube events. We perform a thorough sensitivity study and, given the lack of identified correlation, we place upper limits on the fraction of the observed neutrinos that would be produced in proton-proton or proton-gamma interactions from the population of sources contributing to the UGRB emission and dominating its spatial anisotropy (aka blazars). Our analysis suggests that, under the assumption that there is no intrinsic cutoff and/or hardening of the spectrum above Fermi-LAT energies, and that all gamma-rays from the unresolved blazars dominating the UGRB fluctuation field are produced by neutral pions from p-p (p-gamma) interactions, up to 60% (30%) of such population may contribute to the total neutrino events observed by IceCube. This translates into a O(1%) maximum contribution to the astrophysical high-energy neutrino flux observed by IceCube at 100 TeV.
Nonparametric model for the equations of state of neutron star from deep neural network
Creators: name: Zhou, Wenjie
name: Hu, Jinniu
name: Zhang, Ying
name: Shen, Hong
Publisher: name: arXiv
Year: 2023
Subjects: subject: Nuclear Theory (nucl-th)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: It is of great interest to understand the equation of state (EOS) of the neutron star (NS), whose core includes highly dense matter. However, there are large uncertainties in the theoretical predictions for the EOS of NS. It is useful to develop a new framework, which is flexible enough to consider the systematic error in theoretical predictions and to use them as a best guess at the same time. We employ a deep neural network to perform a non-parametric fit of the EOS of NS using currently available data. In this framework, the Gaussian process is applied to represent the EOSs and the training set data required to close physical solutions. Our model is constructed under the assumption that the true EOS of NS is a perturbation of the relativistic mean-field model prediction. We fit the EOSs of NS using two different example datasets, which can satisfy the latest constraints from the massive neutron stars, NICER, and the gravitational wave of the binary neutron stars. Given our assumptions, we find that a maximum neutron star mass is $2.38^{+0.15}_{-0.13} M_\odot$ or $2.41^{+0.15}_{-0.14}$ at $95\%$ confidence level from two different example datasets. It implies that the $1.4 M_\odot$ radius is $12.31^{+0.29}_{-0.31}$ km or $12.30^{+0.35}_{-0.37}$ km. These results are consistent with results from previous studies using similar priors. It has demonstrated the recovery of the EOS of NS using a nonparametric model.
description: 12 pages, 9 figures, 2 tables, accepted by Astrophysical Journal
Global extraction of the parton-to-pion fragmentation functions at NLO accuracy in QCD
Creators: name: Hernández-Pinto, R. J.
name: Epele, M.
name: de Florian, D.
name: Sassot, R.
name: Stratmann, M.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: In this review, we discuss the results on the parton-to-pion fragmentation functions obtained in a combined NLO fit to data of single-inclusive hadron production in electron-positron annihilation, proton-proton collisions, and lepton-nucleon deep-inelastic scattering. A more complete discussion can be found in Ref. [1].
description: 6 pages, 1 figure. To be published in Journal of Physics Conference Series (IOP). Joint Proceedings of the XV Mexican Workshop on Particles and Fields & the XXX Annual Meeting of the Division of Particles and Fields of the Mexican Physical Society
Performance analysis of indicators of chaos for nonlinear dynamical systems
Creators: name: Bazzani, A.
name: Giovannozzi, M.
name: Montanari, C. E.
name: Turchetti, G.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Dynamical Systems (math.DS)
subject: Chaotic Dynamics (nlin.CD)
subject: Accelerator Physics (physics.acc-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: The efficient detection of chaotic behavior in orbits of a complex dynamical system is an active domain of research. Several indicators have been proposed in the past, and new ones have recently been developed in view of improving the performance of chaos detection by means of numerical simulations. The challenge is to predict chaotic behavior based on the analysis of orbits of limited length. In this paper, the performance analysis of past and recent indicators of chaos, in terms of predictive power, is carried out in detail using the dynamical system characterized by a symplectic Hénon-like cubic polynomial map.
Gas, dust, and the CO-to-molecular gas conversion factor in low-metallicity starbursts
Creators: name: Hunt, L. K.
name: Belfiore, F.
name: Lelli, F.
name: Draine, B. T.
name: Marasco, A.
name: Garcia-Burillo, S.
name: Venturi, G.
name: Combes, F.
name: Weiß, A.
name: Henkel, C.
name: Menten, K. M.
name: Annibali, F.
name: Casasola, V.
name: Cignoni, M.
name: McLeod, A.
name: Tosi, M.
name: Beltran, M.
name: Concas, A.
name: Cresci, G.
name: Ginolfi, M.
name: Kumari, N.
name: Mannucci, F.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The factor relating CO emission to molecular hydrogen column density, XCO, is still subject to uncertainty, in particular at low metallicity. Here, to quantify XCO at two different spatial resolutions, we exploit a dust-based method together with ALMA 12-m and ACA data and HI maps of three nearby metal-poor starbursts, NGC625, NGC1705, and NGC5253. Dust opacity at 250pc resolution is derived based on dust temperatures estimated by fitting two-temperature modified blackbodies to Herschel PACS data. By using the HI maps, we are then able to estimate dust-to-gas ratios in the atomic-gas dominated regions, and infer total gas column densities and H2 column densities as the difference with HI. Finally, from the ACA CO(1-0) maps, we derive XCO. We use a similar technique with 40 pc ALMA 12-m data for the three galaxies, but instead derive dust attenuation at 40 pc resolution from reddening maps based on VLT/MUSE data. At 250 pc resolution, XCO $\sim$ 10^22 - 10^23 cm^-2 / K.km/s, 5-1000 times the Milky Way value, with much larger values than would be expected from a simple metallicity dependence. Instead at 40 pc resolution, XCO again shows large variation, but is roughly consistent with a power-law metallicity dependence, given the Z $\sim$ 1/3 Zsun metal abundances of our targets. The large scatter in both estimations could imply additional parameter dependence, that we have investigated by comparing XCO with the observed velocity-integrated brightness temperatures, ICO, as predicted by recent simulations. Indeed, larger XCO is significantly correlated with smaller ICO, but with slightly different slopes and normalizations than predicted by theory. Such behavior can be attributed to the increasing fraction of CO-faint H2 gas with lower spatial resolution. This confirms the idea the XCO is multi-variate, depending not only on metallicity but also on CO brightness temperature and beam size.
description: A&A, in press (16 figures, 1 appendix)
Revisiting Random Forests in a Comparative Evaluation of Graph Convolutional Neural Network Variants for Traffic Prediction
Creators: name: Ting, Ta Jiun
name: Li, Xiaocan
name: Sanner, Scott
name: Abdulhai, Baher
Publisher: name: arXiv
Year: 2023
Subjects: subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Traffic prediction is a spatiotemporal predictive task that plays an essential role in intelligent transportation systems. Today, graph convolutional neural networks (GCNNs) have become the prevailing models in the traffic prediction literature since they excel at extracting spatial correlations. In this work, we classify the components of successful GCNN prediction models and analyze the effects of matrix factorization, attention mechanism, and weight sharing on their performance. Furthermore, we compare these variations against random forests, a traditional regression method that predates GCNNs by over 15 years. We evaluated these methods using simulated data of two regions in Toronto as well as real-world sensor data from selected California highways. We found that incorporating matrix factorization, attention, and location-specific model weights either individually or collectively into GCNNs can result in a better overall performance. Moreover, although random forest regression is a less compact model, it matches or exceeds the performance of all variations of GCNNs in our experiments. This suggests that the current graph convolutional methods may not be the best approach to traffic prediction and there is still room for improvement. Finally, our findings also suggest that for future research on GCNN for traffic prediction to be credible, researchers must include performance comparison to random forests.
Competition between Bose Einstein Condensation and spin dynamics
Creators: name: Naylor, Bruno
name: Brewczyk, Miroslaw
name: Gajda, Mariusz
name: Gorceix, Olivier
name: Marechal, Etienne
name: Vernac, Laurent
name: Laburthe-Tolra, Bruno
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: We study the impact of spin-exchange collisions on the dynamics of Bose-Einstein condensation, by rapidly cooling a chromium multi-component Bose gas. Despite relatively strong spin-dependent interactions, the critical temperature for Bose-Einstein condensation is reached before the spin-degrees of freedom fully thermalize. The increase in density due to Bose-Einstein condensation then triggers spin dynamics, hampering the formation of condensates in spin excited states. Small metastable spinor condensates are nevertheless produced, and manifest strong spin fluctuations.
description: 5 pages, 4 figures
Imaging of the umbrella motion and tunneling in the ammonia molecule by strong-field ionization
Creators: name: Förster, Johann
name: Plesiat, Etienne
name: Magana, Alvaro
name: Saenz, Alejandro
Publisher: name: arXiv
Year: 2016
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: The geometry-dependent ionization behavior of the ammonia molecule is investigated. Different theoretical approaches for obtaining the ionization yield are compared, all of them showing a strong dependence of the ionization yield on the inversion coordinate at long wavelengths ($\geq$ 800 nm). It is shown how this effect can be exploited to create and probe nuclear wave packets in neutral ammonia using Lochfraß. Furthermore, imaging of a wave packet tunneling through the barrier of a double-well potential in real time is discussed.
description: 11 pages, 12 figures
Families of Optimal Binary Non-MDS Erasure Codes
Creators: name: Gligoroski, Danilo
name: Kralevska, Katina
Publisher: name: arXiv
Year: 2016
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: We introduce a definition for \emph{Families of Optimal Binary Non-MDS Erasure Codes} for $[n, k]$ codes over $GF(2)$, and propose an algorithm for finding those families by using hill climbing techniques over Balanced XOR codes. Due to the hill climbing search, those families of codes have always better decoding probability than the codes generated in a typical Random Linear Network Coding scenario, i.e., random linear codes. We also show a surprising result that for small values of $k$, the decoding probability of our codes in $GF(2)$ is very close to the decoding probability of the codes obtained by Random Linear Network Coding but in the higher finite field $GF(4)$.
description: presented at ISIT 2014
Zenith-Angular Characteristics of Particles in EASs with $E_0 \simeq 10^{18}$ eV According to the Yakutsk Array Data
Creators: name: Glushkov, A. V.
name: Lebedev, K. G.
name: Sabourov, A. V.
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: Particle lateral distributions were investigated in cosmic ray air showers with energy $E_0 \simeq 10^{18}$ eV registered at the Yakutsk array with surface and underground scintillation detectors with $\simeq 1 \times \secθ$~GeV threshold during the period of continuous observations from 1986 to 2016. The analysis covers events with arrival direction zenith angles $θ\le 60^{\circ}$ within five intervals with step $Δ\cosθ= 0.1$. Experimental values were compared to simulation results obtained with the use of CORSIKA code within the framework of QGSJet01 hadron interaction model. The whole dataset points at probable cosmic ray composition which is close to protons.
description: 14 pages, 6 figures. Accepted for publication in Physics of Atomic Nuclei, volume 86 (2023)
Swirls in the Solar Corona
Creators: name: Breu, C.
name: Peter, H.
name: Cameron, R.
name: Solanki, S. K.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Vortex flows have been found in the photosphere, chromosphere and low corona in observations and simulations. It has been suggested that vortices play an important role for channeling energy and plasma into the corona, but the impact of vortex flows on the corona has not directly been studied in a realistic setup. We investigate the role vortices play for coronal heating using high resolution simulations of coronal loops. The vortices are not artificially driven, but arise self-consistently from magnetoconvection. We perform 3D resistive MHD simulations with the MURaM code. Studying an isolated coronal loop in a Cartesian geometry allows us to resolve the structure of the loop interior. We conduct a statistical analysis to determine vortex properties as a function of height from the chromosphere into the corona. We find that the energy injected into the loop is generated by internal coherent motions within strong magnetic elements. A significant part of the resulting Poynting flux is channeled through the chromosphere in vortex tubes forming a magnetic connection between the photosphere and corona. Vortices can form contiguous structures that reach up to coronal heights, but in the corona itself the vortex tubes get deformed and eventually lose their identity with increasing height. Vortices show increased upward directed Poynting flux and heating rate both in the chromosphere and corona, but their effect becomes less pronounced with increasing height. While vortices play an important role for the energy transport and structuring in the chromosphere and low corona, their importance higher up in the atmosphere is less clear since the swirls are less distinguishable from their environment. Vortex tubes reaching the corona show a complex relationship with the coronal emission.
description: 18 pages, 12 figures
Remote Creation of Quantum Coherence
Creators: name: Ma, Teng
name: Zhao, Ming-Jing
name: Fei, Shao-Ming
name: Long, Gui-Lu
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We study remote creation of coherence (RCC) for a quantum system, A, with the help of quantum operations on another system, B, and one-way classical communication.We show that all the nonincoherent quantum states are useful for RCC and all the incoherent-quantum states are not. The necessary and sufficient conditions of RCC for the quantum operations on system B are presented for pure states. The upper bound of average RCC is derived, giving a relation among the entanglement (concurrence), the RCC of the given quantum state, and the RCC of the corresponding maximally entangled state. Moreover, for two-qubit systems we find a simple factorization law for the average remote-created coherence.
description: 6 pages, 1 figure
The hot Jupiter of the magnetically-active weak-line T Tauri star V830 Tau
Creators: name: Donati, J. -F.
name: Yu, L.
name: Moutou, C.
name: Cameron, A. C.
name: Malo, L.
name: Grankin, K.
name: Hébrard, E.
name: Hussain, G. A. J.
name: Vidotto, A. A.
name: Alencar, S. H. P.
name: Haywood, R. D.
name: Bouvier, J.
name: Petit, P.
name: Takami, M.
name: Herczeg, G. J.
name: Gregory, S. G.
name: Jardine, M. M.
name: Morin, J.
name: collaboration, the MaTYSSE
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: We report results of an extended spectropolarimetric and photometric monitoring of the weak-line T Tauri star V830 Tau and its recently-detected newborn close-in giant planet. Our observations, carried out within the MaTYSSE programme, were spread over 91d, and involved the ESPaDOnS and Narval spectropolarimeters linked to the 3.6m Canada-France-Hawaii, the 2m Bernard Lyot and the 8-m Gemini-North Telescopes. Using Zeeman-Doppler Imaging, we characterize the surface brightness distributions, magnetic topologies and surface differential rotation of V830 Tau at the time of our observations, and demonstrate that both distributions evolve with time beyond what is expected from differential rotation. We also report that near the end of our observations, V830 Tau triggered one major flare and two weaker precursors, showing up as enhanced red-shifted emission in multiple spectral activity proxies. With 3 different filtering techniques, we model the radial velocity (RV) activity jitter (of semi-amplitude 1.2km/s) that V830 Tau generates, successfully retrieve the 68m/s RV planet signal hiding behind the jitter, further confirm the existence of V830 Tau b and better characterize its orbital parameters. We find that the method based on Gaussian-process regression performs best thanks to its higher ability at modelling not only the activity jitter, but also its temporal evolution over the course of our observations, and succeeds at reproducing our RV data down to a rms precision of 35m/s. Our result provides new observational constraints on scenarios of star / planet formation and demonstrates the scientific potential of large-scale searches for close-in giant planets around T Tauri stars.
description: MNRAS, in press (17 pages, 15 figures, 5 tables)
Confinedness of an X3.1 class solar flare occurred in NOAA 12192: Analysis from multi-instruments observations
Creators: name: Vasantharaju, N.
name: Zuccarello, F.
name: Ferrente, F.
name: Guglielmino, S. L.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The non-association of coronal mass ejections with high energetic flares is sparse. For this reason, the magnetic conditions required for the confinedness of major flares is a topic of active research. Using multi-instrument observations, we investigated the evolution and effects of confinedness in an X3.1 flare, which occurred in active region (AR) 12192. The decrease of net fluxes in the brightening regions, near the footpoints of the multi-sigmoidal AR in photosphere and chromosphere, indicative of flux cancellation favouring tether-cutting reconnection (TCR), is observed using the magnetic field observations of HMI/SDO and SOT/Hinode, respectively. The analysis of spectropolarimetric data obtained by the Interferometric Bidimensional Spectrometer over the brightening regions suggests untwisting of field lines, which further supports TCR. Filaments near polarity inversion line region, resulted from TCR of low lying sheared loops, undergo merging and form an elongated filament. The temperature and density differences between footpoints of the merged filament, revealed by DEM analysis, caused streaming and counter-streaming of plasma flow along the filament and unloads at its footpoints with an average velocity of $\approx$ 40 km s$^{-1}$. This results in decrease of mass of the filament (density decreased by $>50\%$), leading to its rise and expansion outwards. However, due to strong strapping flux, the filament separates itself instead of erupting. Further, the evolution of non-potential parameters describes the characteristics of confinedness of the flare. Our study suggests that the sigmoid-filament system exhibits upward catastrophe due to mass unloading, but gets suppressed by strong confinement of external poloidal field.
description: Manuscript has 20 pages, 10 figures and accepted for Publication in the ApJ on 23 April 2023
A Cyber Infrastructure for the SKA Telescope Manager
Creators: name: Barbosa, Domingos
name: Barracaa, Joao Paulo
name: Carvalho, Bruno
name: Maia, Dalmiro
name: Gupta, Yashwant
name: Natarajan, Swaminathan
name: Roux, Gerhard Le
name: Swart, Paul
Publisher: name: arXiv
Year: 2016
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: The Square Kilometre Array Telescope Manager (SKA TM) will be responsible for assisting the SKA Operations and Observation Management, carrying out System diagnosis and collecting Monitoring & Control data from the SKA sub-systems and components. To provide adequate compute resources, scalability, operation continuity and high availability, as well as strict Quality of Service, the TM cyber-infrastructure (embodied in the Local Infrastructure - LINFRA) consists of COTS hardware and infrastructural software (for example: server monitoring software, host operating system, virtualization software, device firmware), providing a specially tailored Infrastructure as a Service (IaaS) and Platform as a Service (PaaS) solution. The TM infrastructure provides services in the form of computational power, software defined networking, power, storage abstractions, and high level, state of the art IaaS and PaaS management interfaces. This cyber platform will be tailored to each of the two SKA Phase 1 telescopes (SKA_MID in South Africa and SKA_LOW in Australia) instances, each presenting different computational and storage infrastructures and conditioned by location. This cyber platform will provide a compute model enabling TM to manage the deployment and execution of its multiple components (observation scheduler, proposal submission tools, M&C components, Forensic tools and several Databases, etc). In this sense, the TM LINFRA is primarily focused towards the provision of isolated instances, mostly resorting to virtualization technologies, while defaulting to bare hardware if specifically required due to performance, security, availability, or other requirement.
description: 11 pages, 4 figures, in press in Proceedings of the SPIE Astronomical Telescopes + Instrumentation 2016 (9913-20)
MPEC 2023-R220 : DAILY ORBIT UPDATE (2023 September 15)
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

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.
Precise Masses, Ages of ~1.0 million RGB and RC stars observed by the LAMOST
Creators: name: Wang, Chun
name: Huang, Yang
name: Zhou, Yutao
name: Zhang, Huawei
Publisher: name: arXiv
Year: 2023
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We construct a catalogue of stellar masses and ages for 696,680 red giant branch (RGB) stars, 180,436 primary red clump (RC) stars, and 120,907 secondary RC stars selected from the LAMOST\,DR8. The RGBs, primary RCs, and secondary RCs are identified with the large frequency spacing ($Δν$) and period spacing ($ΔP$), estimated from the LAMOST spectra with spectral SNRs $> 10$ by the neural network method supervised with the seismologic information from LAMOST-Kepler sample stars. The purity and completeness of both RGB and RC samples are better than 95\% and 90\%, respectively. The mass and age of RGBs and RCs are determined again with the neural network method by taking the LAMOST-Kepler giant stars as the training set. The typical uncertainties of stellar mass and age are, respectively, 10\% and 30\% for the RGB stellar sample. For RCs, the typical uncertainties of stellar mass and age are 9\% and 24\%, respectively. The RGB and RC stellar samples cover a large volume of the Milky Way (5 $< R < 20$\,kpc and $|Z| <$\,5\,kpc), which are valuable data sets for various Galactic studies.
description: 13 pages, 16 figures, 1 table, accepted for publication in A&A
Engineering the structural and electronic phases of MoTe2 through W substitution
Creators: name: Rhodes, D.
name: Chenet, D. A.
name: Janicek, B. E.
name: Nyby, C.
name: Lin, Y.
name: Jin, W.
name: Edelberg, D.
name: Mannebach, E.
name: Finney, N.
name: Antony, A.
name: Schiros, T.
name: Klarr, T.
name: Mazzoni, A.
name: Chin, M.
name: Chiu, Y. -c
name: Zheng, W.
name: Zhang, Q. R.
name: Ernst, F.
name: Dadap, J. I.
name: Tong, X.
name: Ma, J.
name: Lou, R.
name: Wang, S.
name: Qian, T.
name: Ding, H.
name: Osgood, R. M.
name: Paley, D. W.
name: Lindenberg, A. M.
name: Huang, P. Y.
name: Pasupathy, A. N.
name: Dubey, M.
name: Hone, J.
name: Balicas, L.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: MoTe$_2$ is an exfoliable transition metal dichalcogenide (TMD) which crystallizes in three symmetries, the semiconducting trigonal-prismatic $2H-$phase, the semimetallic $1T^{\prime}$ monoclinic phase, and the semimetallic orthorhombic $T_d$ structure. The $2H-$phase displays a band gap of $\sim 1$ eV making it appealing for flexible and transparent optoelectronics. The $T_d-$phase is predicted to possess unique topological properties which might lead to topologically protected non-dissipative transport channels. Recently, it was argued that it is possible to locally induce phase-transformations in TMDs, through chemical doping, local heating, or electric-field to achieve ohmic contacts or to induce useful functionalities such as electronic phase-change memory elements. The combination of semiconducting and topological elements based upon the same compound, might produce a new generation of high performance, low dissipation optoelectronic elements. Here, we show that it is possible to engineer the phases of MoTe$_2$ through W substitution by unveiling the phase-diagram of the Mo$_{1-x}$W$_x$Te$_2$ solid solution which displays a semiconducting to semimetallic transition as a function of $x$. We find that only $\sim 8$ \% of W stabilizes the $T_d-$phase at room temperature. Photoemission spectroscopy, indicates that this phase possesses a Fermi surface akin to that of WTe$_2$.
description: 10 paged, 5 pages, supplementary information not included
Anomalous transport in cellular flows: The role of initial conditions and aging
Creators: name: Pöschke, Patrick
name: Sokolov, Igor M.
name: Nepomnyashchy, Alexander A.
name: Zaks, Michael A.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: We consider the diffusion-advection problem in two simple cellular flow models (often invoked as examples for subdiffusive tracer's motion) and concentrate on the intermediate time range, in which the tracer's motion indeed may show subdiffusion. We have performed extensive numerical simulations of the systems under different initial conditions, and show that the pure intermediate-time subdiffusion regime is only evident when the particles start at the border between different cells, i.e. at the separatrix, and is less pronounced or absent for other initial conditions. The motion moreover shows quite peculiar aging properties which are also mirrored in the behavior of the time-averaged mean squared displacement for single trajectories. This kind of behavior is due to the complex motion of tracers trapped inside the cell, and is absent in classical models based on continuous time random walks (CTRW) with no dynamics in the trapped state.
description: 8 pages, 6 figures
Identification of Extended Emission Gamma-Ray-Bursts Candidates using Machine Learning
Creators: name: Garcia-Cifuentes, K.
name: Becerra, R. L.
name: De Colle, F.
name: Cabrera, J. I.
name: del Burgo, C.
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Gamma-Ray bursts (GRBs) have been traditionally classified based on their duration. The increasing number of extended emission (EE) GRBs, lasting typically more than 2 seconds but with properties similar to those of a short GRBs, challenges the traditional classification criteria. In this work, we use the t-Distributed Stochastic Neighbor Embedding (t-SNE), a machine learning technique, to classify GRBs. We present the results for GRBs observed until July 2022 by the Swift/BAT instrument in all its energy bands. We show the effects of varying the learning rate and perplexity parameters as well as the benefit of pre-processing the data by a non-parametric noise reduction technique FABADA. Consistently with previous works, we show that the t-SNE method separates GRBs in two subgroups. We also show that EE GRBs reported by various authors under different criteria tend to cluster in a few regions of our t-SNE maps, and identify seven new EE GRB candidates by using the gamma-ray data provided by the automatic pipeline of Swift/BAT and the proximity with previously identified EE GRBs.
description: Accepted for publication in ApJ
An unusually low-density super-Earth transiting the bright early-type M-dwarf GJ 1018 (TOI-244)
Creators: name: Castro-González, A.
name: Demangeon, O. D. S.
name: Lillo-Box, J.
name: Lovis, C.
name: Lavie, B.
name: Adibekyan, V.
name: Acuña, L.
name: Deleuil, M.
name: Aguichine, A.
name: Osorio, M. R. Zapatero
name: Tabernero, H. M.
name: Davoult, J.
name: Alibert, Y.
name: Santos, N.
name: Sousa, S. G.
name: Antoniadis-Karnavas, A.
name: Borsa, F.
name: Winn, J. N.
name: Prieto, C. Allende
name: Figueira, P.
name: Jenkins, J. M.
name: Sozzetti, A.
name: Damasso, M.
name: Silva, A. M.
name: Astudillo-Defru, N.
name: Barros, S. C. C.
name: Bonfils, X.
name: Cristiani, S.
name: Di Marcantonio, P.
name: Hernández, J. I. González
name: Curto, G. Lo
name: Martins, C. J. A. P.
name: Nunes, N. J.
name: Palle, E.
name: Pepe, F.
name: Seager, S.
name: Mascareño, A. Suárez
Publisher: name: arXiv
Year: 2023
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Small planets located at the lower mode of the bimodal radius distribution are generally assumed to be composed of iron and silicates in a proportion similar to that of the Earth. However, recent discoveries are revealing a new group of low-density planets that are inconsistent with that description. We intend to confirm and characterize the TESS planet candidate TOI-244.01, which orbits the bright ($K$ = 7.97 mag), nearby ($d$ = 22 pc), and early-type (M2.5 V) M-dwarf star GJ 1018 with an orbital period of 7.4 days. We used Markov Chain Monte Carlo methods to model 57 precise radial velocity measurements acquired by the ESPRESSO spectrograph together with TESS photometry and complementary HARPS data. We find TOI-244 b to be a super-Earth with a radius of $R_{\rm p}$ = 1.52 $\pm$ 0.12 $\rm R_{\oplus}$ and a mass of $M_{\rm p}$ = 2.68 $\pm$ 0.30 $\rm M_{\oplus}$. These values correspond to a density of $ρ$ = 4.2 $\pm$ 1.1 $\rm g \cdot cm^{-3}$, which is below what would be expected for an Earth-like composition. We find that atmospheric loss processes may have been efficient to remove a potential primordial hydrogen envelope, but high mean molecular weight volatiles such as water could have been retained. Our internal structure modeling suggests that TOI-244 b has a $479^{+128}_{-96}$ km thick hydrosphere over a 1.17 $\pm$ 0.09 $\rm R_{\oplus}$ solid structure composed of a Fe-rich core and a silicate-dominated mantle compatible with that of the Earth. On a population level, we find two tentative trends in the density-metallicity and density-insolation parameter space for the low-density super-Earths, which may hint at their composition. With a 8$\%$ precision in radius and 12$\%$ precision in mass, TOI-244 b is among the most precisely characterized super-Earths, which, together with the likely presence of an extended hydrosphere, makes it a key target for atmospheric observations.
description: Accepted for publication in A&A
An Eigenshapes Approach to Compressed Signed Distance Fields and Their Utility in Robot Mapping
Creators: name: Canelhas, Daniel R.
name: Schaffernicht, Erik
name: Stoyanov, Todor
name: Lilienthal, Achim J.
name: Davison, Andrew J.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences
subject: 94A08

description: In order to deal with the scaling problem of volumetric map representations we propose spatially local methods for high-ratio compression of 3D maps, represented as truncated signed distance fields. We show that these compressed maps can be used as meaningful descriptors for selective decompression in scenarios relevant to robotic applications. As compression methods, we compare using PCA-derived low-dimensional bases to non-linear auto-encoder networks and novel mixed architectures that combine both. Selecting two application-oriented performance metrics, we evaluate the impact of different compression rates on reconstruction fidelity as well as to the task of map-aided ego-motion estimation. It is demonstrated that lossily compressed distance fields used as cost functions for ego-motion estimation, can outperform their uncompressed counterparts in challenging scenarios from standard RGB-D data-sets.
description: 7 pages, 8 figures
Nonlinear Stochastic Dynamics of Complex Systems, III: Noneqilibrium Thermodynamics of Self-Replication Kinetics
Creators: name: Saakian, David B.
name: Qian, Hong
Publisher: name: arXiv
Year: 2016
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: We briefly review the recently developed, Markov process based isothermal chemical thermodynamics for nonlinear, driven mesoscopic kinetic systems. Both the instantaneous Shannon entropy {\boldmath $S[p_α(t)]$} and relative entropy {\boldmath $F[p_α(t)]$}, defined based on probability distribution {\boldmath $\{p_α(t)\}$}, play prominent roles. The theory is general; and as a special case when a chemical reaction system is situated in an equilibrium environment, it agrees perfectly with Gibbsian chemical thermodynamics: {\boldmath $k_BS$} and {\boldmath $k_BTF$} become thermodynamic entropy and free energy, respectively. We apply this theory to a fully reversible autocatalytic reaction kinetics, represented by a Delbrück-Gillespie process, in a chemostatic nonequilibrium environment. The open, driven chemical system serves as an archetype for biochemical self-replication. The significance of {\em thermodynamically consistent} kinetic coarse-graining is emphasized. In a kinetic system where death of a biological organism is treated as the reversal of its birth, the meaning of mathematically emergent "dissipation", which is not related to the heat measured in terms of {\boldmath $k_BT$}, remains to be further investigated.
description: 10 page
Theoretical photo-disintegration of $^{16}$O
Creators: name: Katsuma, M.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Nuclear Theory (nucl-th)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: The photodisintegration of $^{16}$O is predicted to be dominated by $E$2 excitation in the vicinity of the $α$-particle threshold. The reaction rates of $^{12}$C($α$,$γ$)$^{16}$O are expected to be determined from this reaction.
description: 3 pages, 2 figures, Proceedings of Nuclei in the Cosmos (NIC-XIV). 19-24 June 2016, Niigata, Japan
An Order Statistics Approach to the Halo Model for Galaxies
Creators: name: Paul, Niladri
name: Paranjape, Aseem
name: Sheth, Ravi K.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We use the Halo Model to explore the implications of assuming that galaxy luminosities in groups are randomly drawn from an underlying luminosity function. We show that even the simplest of such order statistics models -- one in which this luminosity function $p(L)$ is universal -- naturally produces a number of features associated with previous analyses based on the `central plus Poisson satellites' hypothesis. These include the monotonic relation of mean central luminosity with halo mass, the Lognormal distribution around this mean, and the tight relation between the central and satellite mass scales. In stark contrast to observations of galaxy clustering, however, this model predicts $\textit{no}$ luminosity dependence of large scale clustering. We then show that an extended version of this model, based on the order statistics of a $\textit{halo mass dependent}$ luminosity function $p(L|m)$, is in much better agreement with the clustering data as well as satellite luminosities, but systematically under-predicts central luminosities. This brings into focus the idea that central galaxies constitute a distinct population that is affected by different physical processes than are the satellites. We model this physical difference as a statistical brightening of the central luminosities, over and above the order statistics prediction. The magnitude gap between the brightest and second brightest group galaxy is predicted as a by-product, and is also in good agreement with observations. We propose that this order statistics framework provides a useful language in which to compare the Halo Model for galaxies with more physically motivated galaxy formation models
description: 16 pages, 18 figures, submitted to MNRAS
Quasi-two-body decays $B_c\to D^*h\to Dπh$ in the perturbative QCD
Creators: name: Zhao, Yan-Chao
name: Zhang, Zhi-Qing
name: Zhang, Zi-Yu
name: Sun, Zhi-Jie
name: Meng, Qiu-Bo
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: In this work, we investigate the quasi-two-body decays $B_c\to D^*h\to Dπh$ with $h = (K^0,π^0,η,η^{\prime})$ using the perturbative QCD(PQCD) approach. The description of final state interactions between the $Dπ$ pair is achieved through the two-meson distribution amplitudes(DAs), which are normalized to the time-like form factor. The PQCD predictions on the branching ratios of the quasi-two-body decays $B_c\to D^*h\to Dπh$ show an obvious hierarchy: $Br(B_{c}^+ \to D^{*+} K^{0}\to D^0π^+K^{0})=({5.22}_{-0.74}^{+0.86})\times{10}^{-6}, Br(B_{c}^+ \to D^{*+} π^{0}\to D^0π^+π^{0})=(0.93\pm0.26)\times{10}^{-7}, Br(B_{c}^+ \to D^{*+} η\to D^0π^+η) =({2.83}_{-0.52}^{+0.59})\times{10}^{-8}$ and $Br(B_{c}^+ \to D^{*+} η^\prime\to D^0π^+η^\prime)=({1.89}_{-0.36}^{+0.40})\times{10}^{-8}$. From the invariant mass $m_{Dπ}$-dependence of the decay spectrum for each channel, one can find that the branching fraction is concentrated in a narrow region around the $D^{*}$ pole mass. So one can obtain the branching ratios for the corresponding two-body decays $B_c\to D^{*+}h$ under the narrow width approximation. We find that the branching ratios of the decays $B_c\to D^{*+}h$ are consistent well with the previous PQCD calculations within errors. These predictions will be tested by the future experiments.
description: 12 pages, 3 figures, accepted for publication in Chin. Phys. C
Existence and multiplicity of solutions for a nonlinear Schrödinger equation with non-local regional diffusion
Creators: name: Alves, Claudianor O.
name: Ledesma, César E. Torres
Publisher: name: arXiv
Year: 2016
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 45G05, 35J60, 35B25

description: In this article we are interested in the following non-linear Schrödinger equation with non-local regional diffusion $$ (-Δ)_{ρ_ε}^αu + u = f(u) \hbox{ in } \mathbb{R}^n, \quad u \in H^α(\mathbb{R}^n), \qquad\qquad(P_ε) $$ where $ε>0$, $0< α< 1$, $(-Δ)_{ρ_ε}^α$ is a variational version of the regional laplacian, whose range of scope is a ball with radius $ρ_ε(x)=ρ(εx)>0$, where $ρ$ is a continuous function. We give general conditions on $ρ$ and $f$ which assure the existence and multiplicity of solution for $(P_ε)$.
description: arXiv admin note: text overlap with arXiv:1311.0708 by other authors
(433) Eros and (25143) Itokawa surface properties from reflectance spectra
Creators: name: Korda, David
name: Kohout, Tomáš
name: Flanderová, Kateřina
name: Vincent, Jean-Baptiste
name: Penttilä, Antti
Publisher: name: arXiv
Year: 2023
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Context. Upcoming space missions will provide us with surface-resolved NEA reflectance spectra. Neural networks are useful tools for analysing reflectance spectra and determining material composition with high precision and low processing time. Aims. We applied neural-network models on disk-resolved spectra of the Eros and Itokawa asteroids observed by the NEAR Shoemaker and Hayabusa spacecraft. With this approach, the mineral variations or intensity of space weathering can be mapped. Methods. We tested two types of convolutional neural networks. The first one was trained using asteroid reflectance spectra with known taxonomy classes. The other one used silicate reflectance spectra with assigned mineral abundances and compositions. Results. The reliability of the classification model depends on the resolution of reflectance spectra. Typical F1 score and Cohen's $κ_C$ values decrease from about 0.90 for high-resolution spectra to about 0.70 for low-resolution spectra. The predicted silicate composition does not strongly depend on spectrum resolution and coverage of the 2$μ$m band of pyroxene. The typical root mean square error is between 6 and 10 percentage points. For the Eros and Itokawa asteroids, the predicted taxonomy classes favour the S-type and the predicted surface compositions are homogeneous and correspond to the composition of L/LL and LL ordinary chondrites, respectively. On the Itokawa surface, the model identified fresh spots that were connected with craters or coarse-grain areas. Conclusions. The neural network models trained with measured spectra of asteroids and silicate samples are suitable for deriving surface silicate mineralogy with a reasonable level of accuracy. The predicted surface mineralogy is comparable to the mineralogy of returned samples measured in the laboratory. Moreover, the taxonomical predictions can point out locations of fresher areas.
description: 14 pages, 12 figures, 4 tables; plus appendices
Power Monitoring and Control for Large Scale projects: SKA, a case study
Creators: name: Barbosa, Domingos
name: Barraca, João Paulo
name: Maia, Dalmiro
name: Carvalho, Bruno
name: Vieira, Jorge
name: Swart, Paul
name: Roux, Gerhard Le
name: Natarajan, Swaminathan
name: van Ardenne, Arnold
name: Seca, Luis
Publisher: name: arXiv
Year: 2016
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: Large sensor-based science infrastructures for radio astronomy like the SKA will be among the most intensive data-driven projects in the world, facing very high demanding computation, storage, management, and above all power demands. The geographically wide distribution of the SKA and and its associated processing requirements in the form of tailored High Performance Computing (HPC) facilities, require a Greener approach towards the Information and Communications Technologies (ICT) adopted for the data processing to enable operational compliance to potentially strict power budgets. Addressing the reduction of electricity costs, improve system power monitoring and the generation and management of electricity at system level is paramount to avoid future inefficiencies and higher costs and enable fulfillments of Key Science Cases. Here we outline major characteristics and innovation approaches to address power efficiency and long-term power sustainability for radio astronomy projects, focusing on Green ICT for science and Smart power monitoring and control.
description: 11 pages, 3 figures, 3 tables, in press Proceedings of SPIE Astronomical Telescopes + Instrumentation 2016 (9910-25). arXiv admin note: text overlap with arXiv:1402.2783