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Virtual excitations and quantum correlations in ultra-strongly coupled harmonic oscillators under intrinsic decoherence

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arXiv 2022年

作者： Hab-Arrih, Radouan Jellal, Ahmed El Kinani, El Hassan Laboratory of Theoretical Physics Faculty of Sciences Chouaïb Doukkali University PO Box 20 El Jadida24000 Morocco Canadian Quantum Research Center 204-3002 32 Ave VernonBCV1T 2L7 Canada Mathematical Modeling and Scientific Computing Team Department of Mathematics Faculty of Sciences Moulay Ismail University Meknes Morocco

关键词： Ground state

The role of thermal fluctuations and vibrational entropy for the δ-to-α transition in hybrid organic-inorganic perovskites: the FAPbI3 case

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arXiv 2022年

作者： Yin, Junwen Teobaldi, Gilberto Liu, Li-Min Beijing Computational Science Research Center Beijing100193 China School of Physics Beihang University Beijing100083 China Scientific Computing Department STFC UKRI Rutherford Appleton Laboratory Harwell Campus Didcot OX11 0QX United Kingdom School of Chemistry University of Southampton Highfield SouthamptonSO17 1BJ United Kingdom

Formamidinium lead halide (FAPbI3), as a typical hybrid organic-inorganic perovskite, has attracted considerable interest due to its band gap suitable for visible light absorption and good thermal stability. A barrier to the use of FAPbI3 in commercial, stable devices is its unwanted black-to-yellow (non-perovskite to perovskite, commonly known as δ-to-α) phase transition at around 300 K. The intrinsic mechanisms of such phase transition are far from clear, being the detailed structural description for the α-phase still missing. By combined Density Functional Theory (DFT) calculations, lattice dynamics analysis and DFT molecular dynamics simulations, we assign the α-phase to the highly dynamic tetragonal phase, with the high-symmetry cubic structure emerging as a dynamically unstable maximum in the system's potential energy landscape. We demonstrate computationally that the diffraction-observed cubic structure is the result of the averaging of different tetragonal distortions sampled in the experimental detection time scale as a result of the enhanced FA dynamics, instead of a static system of cubic symmetry. Further finite-temperature Gibbs free energy calculations confirm that the δ-to-α transition should be considered as a hexagonal-to-tetragonal transition in contrast to the previous hexagonal-to-cubic assignment. More importantly, the simulations indicate that the driving force of the process is the vibrational entropy difference rather than the rotational entropy as previously proposed. These results point out the dynamical nature of the α-phase, the importance of the overlooked tetragonal structure, and the key role of the vibrational entropy in perovskite-related phase transitions, the harnessing of which is critical for successful uptake of ABX3 hybrid organic-inorganic perovskites in commercial applications. © 2022, CC BY-NC-ND.

关键词： Potential energy

The neutron star mass, distance, and inclination from precision timing of the brilliant millisecond pulsar J0437−4715

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arXiv 2024年

作者： Reardon, Daniel J. Bailes, Matthew Shannon, Ryan M. Flynn, Chris Askew, Jacob Bhat, N.D. Ramesh Chen, Zu-Cheng Curylo, Malgorzata Feng, Yi Hobbs, George B. Kapur, Agastya Kerr, Matthew Liu, Xiaojin Manchester, Richard N. Mandow, Rami Mishra, Saurav Russell, Christopher J. Shamohammadi, Mohsen Zhang, Lei Zic, Andrew Centre for Astrophysics and Supercomputing Swinburne University of Technology P.O. Box 218 HawthornVIC3122 Australia OzGrav The Australian Research Council Centre of Excellence for Gravitational Wave Discovery HawthornVIC3122 Australia International Centre for Radio Astronomy Research Curtin University BentleyWA6102 Australia Department of Physics Synergetic Innovation Center for Quantum Effects and Applications Hunan Normal University Hunan Changsha410081 China Institute of Interdisciplinary Studies Hunan Normal University Hunan Changsha410081 China Astronomical Observatory University of Warsaw Aleje Ujazdowskie 4 Warsaw00-478 Poland Research Center for Astronomical Computing Zhejiang Laboratory Hangzhou311100 China Australia Telescope National Facility CSIRO Space and Astronomy P.O. Box 76 EppingNSW1710 Australia Space Science Division US Naval Research Laboratory 4555 Overlook Ave SW WashingtonDC20375 United States Faculty of Arts and Sciences Beijing Normal University Zhuhai519087 China Department of Physics and Astronomy MQ Research Centre in Astronomy Astrophysics and Astrophotonics Macquarie University NSW2109 Australia CSIRO Scientific Computing Australian Technology Park Locked Bag 9013 AlexandriaNSW1435 Australia National Astronomical Observatories Chinese Academy of Sciences A20 Datun Road Chaoyang District Beijing100101 China

The observation of neutron stars enables the otherwise impossible study of fundamental physical processes. The timing of binary radio pulsars is particularly powerful, as it enables precise characterization of their (three-dimensional) positions and orbits. PSR J0437−4715 is an important millisecond pulsar for timing array experiments and is also a primary target for the Neutron Star Interior Composition Explorer (NICER). The main aim of the NICER mission is to constrain the neutron star equation of state by inferring the compactness (Mp/R) of the star. Direct measurements of the mass Mp from pulsar timing therefore substantially improve constraints on the radius R and the equation of state. Here we use observations spanning 26 years from Murriyang, the 64-m Parkes radio telescope, to improve the timing model for this pulsar. Among the new precise measurements are the pulsar mass Mp = 1.418 ± 0.044 M☉, distance D = 156.96 ± 0.11 pc, and orbital inclination angle i = 137.506 ±0.016◦, which can be used to inform the X-ray pulse profile models inferred from NICER observations. We demonstrate that these results are consistent between multiple data sets from the Parkes Pulsar Timing Array (PPTA), each modeled with different noise assumptions. Using the longest available PPTA data set, we measure an apparent second derivative of the pulsar spin frequency and discuss how this can be explained either by kinematic effects due to the proper motion and radial velocity of the pulsar or excess low-frequency noise such as a gravitational-wave background. © 2024, CC BY.

关键词： Neutrons

Brain solute transport is more rapid in periarterial than perivenous spaces

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Research Square

research Square 2021年

作者： Vinje, Vegard Bakker, Erik Nicolaas Theodorus Petrus Rognes, Marie E. Department of Scientific Computing and Numerical Analysis Simula Research Laboratory Martin Linges vei 25 Fornebu 1364 Norway Amsterdam University Medical Center Dept. of Biomedical Engineering and Physics Meibergdreef 9 Amsterdam1105 AZ Netherlands University of Bergen Department of Mathematics Bergen Norway

Background: Perivascular fluid flow, of cerebrospinal or interstitial fluid in spaces surrounding brain blood vessels, is recognized as a key component underlying brain transport and clearance. An important open question is how and to what extent differences in vessel type or geometry affect perivascular fluid flow and transport. Methods: Using computational modelling in both idealized and image-based geometries, we study and compare fluid flow and solute transport in pial (surface) periarterial and perivenous spaces. Results: Our findings demonstrate that differences in geometry between arterial and venous pial perivascular spaces (PVSs) lead to higher net CSF flow, more rapid tracer transport and earlier arrival times of injected tracers in periarterial spaces compared to perivenous spaces. Conclusions: These findings can explain the experimentally observed rapid appearance of tracers around arteries, and the delayed appearance around veins without the need of a circulation through the parenchyma, but rather by direct transport along the PVSs. © 2021, CC BY.

关键词： Blood vessels

Template bank for sub solar mass compact binary mergers in the fourth observing run of Advanced LIGO, Advanced Virgo, and KAGRA

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arXiv 2024年

作者： Hanna, Chad Kennington, James Niu, Wanting Sakon, Shio Singh, Divya Adhicary, Shomik Baral, Pratyusava Baylor, Amanda Cannon, Kipp Caudill, Sarah Cousins, Bryce Creighton, Jolien D.E. Ewing, Becca Fong, Heather George, Richard N. Godwin, Patrick Harada, Reiko Huang, Yun-Jing Huxford, Rachael Joshi, Prathamesh Kuwahara, Soichiro Li, Alvin K.Y. Magee, Ryan Meacher, Duncan Messick, Cody Morisaki, Soichiro Mukherjee, Debnandini Pace, Alexander Posnansky, Cort Ray, Anarya Sachdev, Surabhi Schmidt, Stefano Shah, Urja Tapia, Ron Tsukada, Leo Ueno, Koh Viets, Aaron Wade, Leslie Wade, Madeline Yarbrough, Zach Zhang, Noah Department of Physics The Pennsylvania State University University ParkPA16802 United States Institute for Gravitation and the Cosmos The Pennsylvania State University University ParkPA16802 United States Department of Astronomy and Astrophysics The Pennsylvania State University University ParkPA16802 United States Institute for Computational and Data Sciences The Pennsylvania State University University ParkPA16802 United States Department of Physics University of California BerkeleyCA94720 United States Leonard E. Parker Center for Gravitation Cosmology and Astrophysics University of Wisconsin-Milwaukee MilwaukeeWI53201 United States RESCEU The University of Tokyo Tokyo113-0033 Japan Department of Physics University of Massachusetts DartmouthMA02747 United States Center for Scientific Computing and Data Science Research University of Massachusetts DartmouthMA02747 United States Department of Physics University of Illinois UrbanaIL61801 United States Department of Physics and Astronomy University of British Columbia VancouverBCV6T 1Z4 Canada Graduate School of Science The University of Tokyo Tokyo113-0033 Japan Center for Gravitational Physics University of Texas at Austin AustinTX78712 United States LIGO Laboratory California Institute of Technology MS 100-36 PasadenaCA91125 United States LIGO Laboratory California Institute of Technology PasadenaCA91125 United States MIT Kavli Institute for Astrophysics and Space Research Massachusetts Institute of Technology CambridgeMA02139 United States Institute for Cosmic Ray Research The University of Tokyo 5-1-5 Kashiwanoha Chiba Kashiwa277-8582 Japan NASA Marshall Space Flight Center HuntsvilleAL35811 United States Center for Space Plasma and Aeronomic Research University of Alabama in Huntsville HuntsvilleAL35899 United States Center of Interdisciplinary Education and Research in Astrophysics Northwestern University IL60201 United States School of Physics Georgia Insti

Matched-filtering searches for gravitational-wave signals from compact binary mergers employ template banks which are a collection of modeled waveforms described by unique intrinsic parameters. We present two banks designed for low-latency and archive sub-solar mass (SSM) searches in data from the fourth observing run of LIGO-Virgo-KAGRA, and demonstrate the efficacy of the banks via simulated signals. Further, we introduce a set of modifications to the geometric, manifold algorithm [1, 2] that allow the method to work for exceedingly low component masses necessary for SSM bank production. The archive search bank contains a total of 3,452,006 templates, and covers a mass parameter space of 0.2 to 10 M☉ in the larger component and 0.2 to 1.0 M☉ in the smaller component, the spin parameter space of −0.9 to 0.9 for masses above 0.5 M☉ and −0.1 to 0.1 for masses below 0.5 M☉, and the mass ratio parameter space of 1 to 10. The PSD used was from a week of the first half of the fourth observing run of Advanced LIGO, Advanced Virgo, and KAGRA, and the low frequency cutoff was set to 45 Hz with a maximum waveform duration of 128 seconds. The bank simulations performed using SBank have shown that the banks presented in this paper have sufficient efficacy for use in their respective searches. Copyright © 2024, The Authors. All rights reserved.

关键词： Gravity waves

Bayesian Inference for Gravitational Waves from Binary Neutron Star Mergers in Third Generation Observatories

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Physical Review Letters 2021年第8期127卷 081102-081102页

作者： Rory Smith Ssohrab Borhanian Bangalore Sathyaprakash Francisco Hernandez Vivanco Scott E. Field Paul Lasky Ilya Mandel Soichiro Morisaki David Ottaway Bram J. J. Slagmolen Eric Thrane Daniel Töyrä Salvatore Vitale School of Physics and Astronomy Monash University Victoria 3800 Australia OzGrav: The ARC Centre of Excellence for Gravitational Wave Discovery Clayton Victoria 3800 Australia Institute for Gravitation and the Cosmos Department of Physics Pennsylvania State University University Park Pennsylvania 16802 USA Department of Astronomy and Astrophysics Pennsylvania State University University Park Pennsylvania 16802 USA School of Physics and Astronomy Cardiff University Cardiff CF24 3AA United Kingdom Department of Mathematics and Center for Scientific Computing and Visualization Research University of Massachusetts Dartmouth Massachusetts 02747 USA Department of Physics University of Wisconsin-Milwaukee Milwaukee Wisconsin 53201 USA OzGrav University of Adelaide Adelaide South Australia 5005 Australia OzGrav ANU Centre for Gravitational Astrophysics Research Schools of Physics and Astronomy and Astrophysics The Australian National University Australian Capital Territory 2601 Australia LIGO Laboratory Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA Department of Physics and Kavli Institute for Astrophysics and Space Research Massachusetts Institute of Technology 77 Massachusetts Avenue Cambridge Massachusetts 02139 USA

Third generation (3G) gravitational-wave detectors will observe thousands of coalescing neutron star binaries with unprecedented fidelity. Extracting the highest precision science from these signals is expected to be challenging owing to both high signal-to-noise ratios and long-duration signals. We demonstrate that current Bayesian inference paradigms can be extended to the analysis of binary neutron star signals without breaking the computational bank. We construct reduced-order models for ∼90-min-long gravitational-wave signals covering the observing band (5–2048 Hz), speeding up inference by a factor of ∼1.3×104 compared to the calculation times without reduced-order models. The reduced-order models incorporate key physics including the effects of tidal deformability, amplitude modulation due to Earth’s rotation, and spin-induced orbital precession. We show how reduced-order modeling can accelerate inference on data containing multiple overlapping gravitational-wave signals, and determine the speedup as a function of the number of overlapping signals. Thus, we conclude that Bayesian inference is computationally tractable for the long-lived, overlapping, high signal-to-noise-ratio events present in 3G observatories.

关键词： Experimental studies of gravity Gravitational waves

Anomaly Detection under Coordinate Transformations

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arXiv 2022年

作者： Kasieczka, Gregor Mastandrea, Radha Mikuni, Vinicius Nachman, Benjamin Pettee, Mariel Shih, David Institut für Experimentalphysik Universität Hamburg Hamburg22761 Germany Department of Physics University of California BerkeleyCA94720 United States Physics Division Lawrence Berkeley National Laboratory BerkeleyCA94720 United States National Energy Research Scientific Computing Center Berkeley Lab BerkeleyCA94720 United States Berkeley Institute for Data Science University of California BerkeleyCA94720 United States New High Energy Theory Center Rutgers University PiscatawayNJ08854 United States

There is a growing need for machine learning-based anomaly detection strategies to broaden the search for Beyond-the-Standard-Model (BSM) physics at the Large Hadron Collider (LHC) and elsewhere. The first step of any anomaly detection approach is to specify observables and then use them to decide on a set of anomalous events. One common choice is to select events that have low probability density. It is a well-known fact that probability densities are not invariant under coordinate transformations, so the sensitivity can depend on the initial choice of coordinates. The broader machine learning community has recently connected coordinate sensitivity with anomaly detection and our goal is to bring awareness of this issue to the growing high energy physics literature on anomaly detection. In addition to analytical explanations, we provide numerical examples from simple random variables and from the LHC Olympics Dataset that show how using probability density as an anomaly score can lead to events being classified as anomalous or not depending on the coordinate frame. © 2022, CC BY.

关键词： Anomaly detection

Evidence of large recoil velocity from a black hole merger signal

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arXiv 2022年

作者： Varma, Vijay Biscoveanu, Sylvia Islam, Tousif Shaik, Feroz H. Haster, Carl-Johan Isi, Maximiliano Farr, Will M. Field, Scott E. Vitale, Salvatore Am Mühlenberg 1 Potsdam14476 Germany LIGO Laboratory Massachusetts Institute of Technology CambridgeMA02139 United States Department of Physics Kavli Institute for Astrophysics and Space Research Massachusetts Institute of Technology 77 Massachusetts Ave CambridgeMA02139 United States Department of Mathematics University of Massachusetts DartmouthMA02747 United States Center for Scientific Computing and Data Science Research University of Massachusetts DartmouthMA02747 United States Center for Computational Astrophysics Flatiron Institute New YorkNY10010 United States Department of Physics and Astronomy Stony Brook University Stony Brook NY11794 United States

The final black hole left behind after a binary black hole merger can attain a recoil velocity, or a "kick", reaching values up to 5000 km/s. This phenomenon has important implications for gravitational wave astronomy, black hole formation scenarios, testing general relativity, and galaxy evolution. We consider the gravitational wave signal from the binary black hole merger GW200129_065458 (henceforth referred to as GW200129), which has been shown to exhibit strong evidence of orbital precession. Using numerical relativity surrogate models, we constrain the kick velocity of GW200129 to vf (Equation presented) km/s or vf 698 km/s (one-sided limit), at 90% credibility. This marks the first identification of a large kick velocity for an individual gravitational wave event. Given the kick velocity of GW200129, we estimate that there is a less than 0.48% (7.7%) probability that the remnant black hole after the merger would be retained by globular (nuclear star) clusters. Finally, we show that kick effects are not expected to cause biases in ringdown tests of general relativity for this event, although this may change in the future with improved detectors. © 2022, CC BY.

关键词： Merging

Quantum computing hardware for HEP algorithms and sensing

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arXiv 2022年

作者： Alam, M. Sohaib Belomestnykh, Sergey Bornman, Nicholas Cancelo, Gustavo Chao, Yu-Chiu Checchin, Mattia Dinh, Vinh San Grassellino, Anna Gustafson, Erik J. Harnik, Roni McRae, Corey Rae Harrington Huang, Ziwen Kapoor, Keshav Kim, Taeyoon Kowalkowski, James B. Kramer, Matthew J. Krasnikova, Yulia Kumar, Prem Kurkcuoglu, Doga Murat Lamm, Henry Lyon, Adam L. Milathianaki, Despina Murthy, Akshay Mutus, Josh Nekrashevich, Ivan Oh, JinSu Özgüler, A. Barış Perdue, Gabriel Nathan Reagor, Matthew Romanenko, Alexander Sauls, James A. Stefanazzi, Leandro Tubman, Norm M. Venturelli, Davide Wang, Changqing You, Xinyuan van Zanten, David M.T. Zhou, Lin Zhu, Shaojiang Zorzetti, Silvia NASA Ames Research Center Moffett FieldCA94035 United States Mountain ViewCA94043 United States Fermi National Accelerator Laboratory BataviaIL60510 United States Scientific Computing Division Fermi National Accelerator Laboratory BataviaIL60510 United States Northwestern-Fermilab Center for Applied Physics and Superconducting Technologies Northwestern University EvanstonIL60208 United States Graduate Program in Applied Physics Northwestern University EvanstonIL60208 United States Theory Division Fermi National Accelerator Laboratory BataviaIL60510 United States Department of Physics Department of Electrical Computer and Energy Engineering University of Colorado Boulder CO80305 United States National Institute of Standards and Technology Boulder CO80305 United States Department of Physics and Astronomy Northwestern University EvanstonIL60208 United States Ames Laboratory U.S. Department of Energy AmesIA50011 United States Center for Photonic Communication and Computing ECE Department Northwestern University EvanstonIL60208 United States Rigetti Computing Inc. BerkeleyCA94710 United States NASA Ames Research Center Moffett FieldCA94035 United States

Quantum information science harnesses the principles of quantum mechanics to realize computational algorithms with complexities vastly intractable by current computer platforms. Typical applications range from quantum chemistry to optimization problems and also include simulations for high energy physics. The recent maturing of quantum hardware has triggered preliminary explorations by several institutions (including Fermilab) of quantum hardware capable of demonstrating quantum advantage in multiple domains, from quantum computing to communications, to sensing. The Superconducting Quantum Materials and Systems (SQMS) center, led by Fermilab, is dedicated to providing breakthroughs in quantum computing and sensing, mediating quantum engineering and HEP based material science. The main goal of the center is to deploy quantum systems with superior performance tailored to the algorithms used in high energy physics. In this Snowmass paper, we discuss the two most promising superconducting quantum architectures for HEP algorithms, i.e. three-level systems (qutrits) supported by transmon devices coupled to planar devices and multi-level systems (qudits with arbitrary N energy levels) supported by superconducting 3D cavities. For each architecture, we demonstrate exemplary HEP algorithms and identify the current challenges, ongoing work and future opportunities. Furthermore, we discuss the prospects and complexities of interconnecting the different architectures and individual computational nodes. Finally, we review several different strategies of error protection and correction and discuss their potential to improve the performance of the two architectures. This whitepaper seeks to reach out to the HEP community and drive progress in both HEP research and QIS hardware. Copyright © 2022, The Authors. All rights reserved.

关键词： High energy physics