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Dynamics and pattern formation of ring dark solitons in a two-dimensional binary Bose-Einstein condensate with tunable interactions

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Physical Review E 2019年第6期99卷 062216-062216页

作者： Zhang-Ming He L. Wen Ya-Jun Wang G. P. Chen R.-B. Tan C.-Q. Dai Xiao-Fei Zhang College of Science Hunan University of Technology Zhuzhou 412007 China College of Physics and Electronic Engineering Chongqing Normal University Chongqing 400047 China Key Laboratory of Time and Frequency Primary Standards National Time Service Center Chinese Academy of Sciences Xi'an 710600 China School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing 100049 China School of Physics and Mechtronic Engineering Sichuan University of Art and Science Dazhou 635000 China College of Mathematics and Physics Chongqing University of Science and Technology Chongqing 401331 China School of Sciences Zhejiang A&F University Lin'an Zhejiang 311300 China

We investigate the dynamics and pattern formation of two ring dark solitons in a two-dimensional binary Bose-Einstein condensate with tunable intercomponent interaction via numerical simulation of the time-dependent Gross-Pitaevskii equation. Both the black and gray ring dark solitons are considered for cases where the modulation frequency of the intercomponent interaction is resonant or nonresonant with the one of the trapping potential. Our results show that in the presence of periodic modulation of the intercomponent interaction not only are the lifetimes of the ring dark solitons largely extended but also their decaying dynamics are dramatically affected. Before snaking instability sets in, new ring dark solitons are formed, and both the numbers and depths of the ring dark solitons exhibit collective oscillations. With the development of instability, the system exhibits different decaying processes, and a variety of decay profiles, such as vortex necklace, distorted octagon, vortex-antivortex ring, and cross, are formed, showing a strong dependence on the modulation frequency of the intercomponent interaction and the initial depth of the ring dark soliton.

关键词： Bose-Einstein condensates Cold atoms & matter waves Quantum control Ultracold collisions

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Performance study of complex application programs on tens of thousands cores

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Ruan Jian Xue Bao/Journal of Software 2011年第SUPPL. 2期22卷 157-162页

作者： Gao, Xing-Yu Cao, Xiao-Lin Zhao, Wei-Bo Zhang, Ai-Qing Mo, Ze-Yao High Performance Computing Center Institute of Applied Physics and Computational Mathematics Beijing 100094 China Key Laboratory of Science and Technology for National Defense Institute of Applied Physics and Computational Mathematics Beijing 100094 China

Oriented to the large-scale computation on tens of thousands cores, the parallel software infrastructure named JASMIN has released a new version which has improved the enabling techniques and numerical algorithms. With downward compatible programming interfaces, the new version can enhance the scalability of the programs free of application users' effort. To investigate the scalability of the programs based on JASMIN, we test and analyze the performance of five complex application programs on tens of thousands cores of TH-1A supercomputer. These programs were developed for the high-performance computation arising from inertial confinement fusion, material science as well as the high-power microwave. It is shown that four programs achieve a parallel efficiency of over 60% on 42,000 cores and three ones achieve a parallel efficiency of over 45% on 84,000 cores. ©2011 Journal of Software.

关键词： Application programs

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Spin-Triplet Excitonic Insulator: The Case of Semihydrogenated Graphene

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Physical Review Letters 2020年第16期124卷 166401-166401页

作者： Zeyu Jiang Wenkai Lou Yu Liu Yuanchang Li Haifeng Song Kai Chang Wenhui Duan Shengbai Zhang State Key Laboratory of Low-Dimensional Quantum Physics and Collaborative Innovation Center of Quantum Matter Department of Physics Tsinghua University Beijing 100084 China SKLSM Institute of Semiconductors Chinese Academy of Sciences P.O. Box 912 Beijing 100083 China Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Beijing 100088 China Key Lab of advanced optoelectronic quantum architecture and measurement (MOE) and Advanced Research Institute of Multidisciplinary Science Beijing Institute of Technology Beijing 100081 China CAEP Software Center for High Performance Numerical Simulation Beijing 100088 China Beijing Academy of Quantum Information Sciences Beijing 100193 China Institute for Advanced Study Tsinghua University Beijing 100084 China Department of Physics Applied Physics and Astronomy Rensselaer Polytechnic Institute Troy New York 12180 USA

While various excitonic insulators have been studied in the literature, due to the perceived too-small spin splitting, spin-triplet excitonic insulator is rare. In two-dimensional systems such as a semihydrogenated graphene (known as graphone), however, it is possible, as revealed by first-principles calculations coupled with Bethe-Salpeter equation. The critical temperature, given by an effective Hamiltonian, is 11.5 K. While detecting excitonic insulators is still a daunting challenge, the condensation of triplet excitons will result in spin superfluidity, which can be directly measured by a transport experiment. Nonlocal dielectric screening also leads to an unexpected phenomenon, namely, an indirect-to-direct transition crossover between single-particle band and exciton dispersion in the semihydrogenated graphene, which offers yet another test by experiment.

关键词： Excitons Graphene First-principles calculations

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The role of plasma beta in global coronal models: Bringing balance back to the force

arXiv

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arXiv 2023年

作者： Brchnelova, Michaela Kuźma, Blażej Zhang, Fan Lani, Andrea Poedts, Stefaan Centre for Mathematical Plasma Astrophysics KU Leuven Celestijnenlaan 200B Leuven3001 Belgium Shenzhen Key Laboratory of Numerical Prediction for Space Storm Institute of Space Science and Applied Technology Harbin Institute of Technology Shenzhen518055 China Key Laboratory of Solar Activity and Space Weather National Space Science Center Chinese Academy of Sciences Beijing100190 China Institute of Physics University of Maria Curie-Sklodowska ul. Radziszewskiego 10 Lublin20-031 Poland

Context. COolfluid COrona uNstrUcTured (COCONUT) is a global coronal magnetohydrodynamic (MHD) model that has been recently developed and will soon be integrated into the ESA Virtual Space Weather Modelling Centre (VSWMC). In order to achieve robustness and fast convergence to steady-state for numerical simulations with COCONUT, several assumptions and simplifications have been made during its development, such as prescribing filtered photospheric magnetic maps for representing the magnetic field conditions in the lower corona. This filtering leads to smoothing and lower magnetic field values at the inner boundary (i.e., the solar surface), resulting in an unrealistically high plasma β (more than 1 in a large portion of the domain). Aims. In this paper, we examine the effects of prescribing such filtered/smoothed magnetograms in global coronal simulations and formulate a method for achieving more realistic plasma β values and improving the resolution of electromagnetic features without losing computational performance. Methods. We make use of the newly developed COCONUT solver to demonstrate the effects of the highly pre-processed magnetic maps set at the inner boundary and the resulting high plasma β on the features in the computational domain. Then, in our new approach, we shift the inner boundary to 2 R☉ from the original 1.01 R☉ and preserve the prescribed highly filtered magnetic map. With the shifted boundary, naturally, the boundary density and pressure are also adjusted to better represent the considered physical location. This effectively reduces the prescribed plasma β and leads to a more realistic setup. The method is applied on a magnetic dipole, a minimum (2008) and a maximum (2012) solar activity case, to demonstrate its effects. Results. The results obtained with the proposed approach show significant improvements in the resolved density and radial velocity profiles, and far more realistic values of the plasma β at the boundary and inside the computat

关键词： Magnetohydrodynamics

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Optimal verification and fidelity estimation of maximally entangled states

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Physical Review A 2019年第5期99卷 052346-052346页

作者： Huangjun Zhu Masahito Hayashi Department of Physics and Center for Field Theory and Particle Physics Fudan University Shanghai 200433 China State Key Laboratory of Surface Physics Fudan University Shanghai 200433 China Institute for Nanoelectronic Devices and Quantum Computing Fudan University Shanghai 200433 China Collaborative Innovation Center of Advanced Microstructures Nanjing 210093 China Graduate School of Mathematics Nagoya University Nagoya 464-8602 Japan Shenzhen Institute for Quantum Science and Engineering Southern University of Science and Technology Shenzhen 518055 China Centre for Quantum Technologies National University of Singapore 3 Science Drive 2 117542 Singapore

We study the verification of maximally entangled states by virtue of the simplest measurement settings: local projective measurements without adaption. We show that optimal protocols are in one-to-one correspondence with complex projective 2-designs constructed from orthonormal bases. Optimal protocols with minimal measurement settings are in one-to-one correspondence with complete sets of mutually unbiased bases. Based on this observation, optimal protocols are constructed explicitly for any local dimension, which can also be applied to estimating the fidelity with the target state and to detecting entanglement. In addition, we show that incomplete sets of mutually unbiased bases are optimal for verifying maximally entangled states when the number of measurement settings is restricted. Moreover, we construct optimal protocols for the adversarial scenario in which state preparation is not trusted. The number of tests has the same scaling behavior as the counterpart for the nonadversarial scenario; the overhead is no more than three times. We also show that the entanglement of the maximally entangled state can be certified with any given significance level using only one test as long as the local dimension is large enough.

关键词： Quantum entanglement Quantum tomography

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Diagnostics of the solar coronal plasmas by magnetohydrodynamic waves: Magnetohydrodynamic seismology

arXiv

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arXiv 2024年

作者： Nakariakov, Valery M. Zhong, Sihui Kolotkov, Dmitrii Y. Meadowcroft, Rebecca L. Zhong, Yu Yuan, Ding Centre for Fusion Space & Astrophysics Department of Physics University of Warwick CoventryCV4 7AL United Kingdom " Ventspils University of Applied Sciences VentspilsLV-3601 Latvia Shenzhen Key Laboratory of Numerical Prediction for Space Storm Harbin Institute of Technology Shenzhen Guangdong518055 China Key Laboratory of Solar Activity and Space Weather National Space Science Center Chinese Academy of Sciences Beijing100190 China

Macroscopic wave and oscillatory phenomena ubiquitously detected in the plasma of the corona of the Sun are interpreted in terms of magnetohydrodynamic theory. Fast and slow magnetoacoustic waves are clearly distinguished in observations. Properties of coronal magnetohydrodynamic waves are determined by local parameters of the plasma, including the field-aligned filamentation typical for the corona. It makes coronal magnetohydrodynamic waves reliable probes of the coronal plasma structures by the method of magnetohydrodynamic seismology. For example, propagating slow waves indicate the local direction of the guiding magnetic field. Standing, sloshing and propagating slow waves can be used for probing the coronal heating function and the polytropic index. Kink oscillations of coronal plasma loops provide us with the estimations of the absolute value of the magnetic field in oscillating plasma loops. This tutorial introduces several techniques of magnetohydrodynamic seismology of solar coronal plasmas. It includes the description of practical steps in the data acquisition, pre-processing, and processing using the open-access data of the Atmospheric Imaging Assembly on the Solar Dynamics Observatory spacecraft, and elaborated data analysis techniques of motion magnification and Bayesian statistics. © 2024, CC BY-NC-ND.

关键词： Seismology

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Emergence of steady currents due to strong prethermalization

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Physical Review A 2023年第2期107卷 022220-022220页

作者： Xiansong Xu Chu Guo Dario Poletti Science Mathematics and Technology Cluster Singapore University of Technology and Design 8 Somapah Road Singapore 487372 Singapore College of Physics and Electronic Engineering and Center for Computational Sciences Sichuan Normal University Chengdu 610068 China Henan Key Laboratory of Quantum Information and Cryptography Zhengzhou Henan 450000 China Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Department of Physics and Synergetic Innovation Center for Quantum Effects and Applications Hunan Normal University Changsha 410081 China EPD Pillar Singapore University of Technology and Design 8 Somapah Road Singapore 487372 Singapore The Abdus Salam International Centre for Theoretical Physics Strada Costiera 11 34151 Trieste Italy Centre for Quantum Technologies National University of Singapore Singapore 117543 Singapore

A steady current between baths is a manifestation of the prethermalization phenomenon, a quasiequilibrium dynamic process with weak breaking of conserved quantities. We consider two finite nonintegrable many-body baths, each following the eigenstate thermalization hypothesis and each prepared in a random product state with fixed and different energy constraints, i.e., within the mean energy ensemble. Such an initialization, not being constrained to superpositions or mixtures of many-body eigenstates, opens the door to experimental realization and also significantly simplifies numerical simulations. We show that such a dynamic process is typical as the current variance decreases exponentially with respect to the size of baths. We also demonstrate that the emerging current is prethermalized in a strong sense, analogous to strong thermalization, meaning that the current values stay close to the microcanonical one most of the time.

关键词： Eigenstate thermalization Nonequilibrium statistical mechanics Open quantum systems & decoherence Nonequilibrium systems

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Four-Fold Composite Structures and Triple Coherent Interfaces Endow Exceptional Mechanical Properties of an Fecrnialti High-Entropy Alloy

SSRN

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SSRN 2024年

作者： Wen, Donghui Jiang, Beibei Gao, Mengqi Huang, Zhaowen Kong, Fengyu Wang, Anding Wang, Qing Wang, Biao Liu, Chain-Tsuan Research Institute of Interdisciplinary Science School of Materials Science and Engineering Dongguan University of Technology Dongguan523808 China Analysis and Test Center Guangdong University of Technology Guangzhou510006 China Xinjiang Key Laboratory of Solid State Physics and Devices School of Physical Science and Technology Xinjiang University Ürümqi830046 China Hong Kong Institute for Advanced Study Mechanical Behavior Division Shenyang National Laboratory for Materials Science City University of Hong Kong Hong Kong School of Materials Science and Engineering Dalian University of Technology Dalian116024 China Department of Materials Science and Engineering China Sino-French Institute of Nuclear Engineering and Technology China

Introducing additional phases and constructing composite structures in BCC-based high-entropy alloys (HEAs) have recently been a hot spot for synergistically enhancing the strength and ductility at room and elevated temperatures. Here, we report a novel cost-efficiency (FeCrNi)85(AlTi)15 HEA that composed of four-fold composite structures with triple BCC/L21, L21/BCC and FCC/L12 coherent interfaces. The rationally introduction of ductile FCC phase in brittle BCC and L21 phases endows this composite alloy with an exceptional compressive plasticity of 37% at room-temperature. The well-controlled L21, BCC and L12 nano-particles coherently precipitate in BCC, L21 and FCC matrix phases, respectively, resulting in the super-high strength of 1850 MPa, outperforming other B2/L21-strengthened BCC HEAs. The triple coherent interfaces stabilize the composite microstructures and lead to the excellent yield strength at elevated temperatures (850 MPa at 700 °C, 395 MPa at 800 °C and 190 MPa at 900 °C). It is found that the FCC/L12 and L21/BCC composite phases can exhibit a high thermal stability even at 900 °C, which can partially compensate the strength decline from BCC/L21 phase dynamic recrystallization. These results obtain a new strategy for overcoming the drawback of inadequate deformability in BCC-based alloys and developing new composite materials for high-temperature applications. © 2024, The Authors. All rights reserved.

关键词： Precipitation (chemical)

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Observing Geometry of Quantum States in a Three-Level System

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Physical Review Letters 2020年第15期125卷 150401-150401页

作者： Jie Xie Aonan Zhang Ningping Cao Huichao Xu Kaimin Zheng Yiu-Tung Poon Nung-Sing Sze Ping Xu Bei Zeng Lijian Zhang National Laboratory of Solid State Microstructures Key Laboratory of Intelligent Optical Sensing and Manipulation (Ministry of Education) College of Engineering and Applied Sciences and School of Physics Nanjing University Nanjing 210093 China Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing 210093 China Department of Mathematics & Statistics University of Guelph Guelph N1G 2W1 Ontario Canada Institute for Quantum Computing University of Waterloo Waterloo N2L 3G1 Ontario Canada Department of Mathematics Iowa State University Ames Iowa 50011 USA Department of Applied Mathematics The Hong Kong Polytechnic University 999077 Hong Kong China Institute for Quantum Information & State Key Laboratory of High Performance Computing College of Computer National University of Defense Technology Changsha 410073 China Department of Physics The Hong Kong University of Science and Technology Clear Water Bay Kowloon 999077 Hong Kong China

In quantum mechanics, geometry has been demonstrated as a useful tool for inferring nonclassical behaviors and exotic properties of quantum systems. One standard approach to illustrate the geometry of quantum systems is to project the quantum state space onto the Euclidean space via measurements of observables on the system. Despite the great success of this method in studying two-level quantum systems (qubits) with the celebrated Bloch sphere representation, it is still difficult to reveal the geometry of multidimensional quantum systems. Here we report the first experiment measuring the geometry of such projections beyond the qubit. Specifically, we observe the joint numerical ranges of a triple of observables in a three-level photonic system, providing a complete classification of these ranges. We further show that the geometry of different classes reveals ground-state degeneracies of a Hamiltonian as a linear combination of the observables, which is related to quantum phases in the thermodynamic limit. Our results offer a versatile geometric approach for exploring the properties of higher-dimensional quantum systems.

关键词： Geometric & topological phases Quantum foundations Quantum measurements Quantum phase transitions

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New test on general relativity using galaxy-galaxy lensing with astronomical surveys

arXiv

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arXiv 2019年

作者： Chen, Zhaoting Luo, Wentao Cai, Yi-Fu Saridakis, Emmanuel N. Department of Astronomy School of Physical Sciences University of Science and Technology of China Hefei Anhui230026 China CAS Key Laboratory for Research in Galaxies and Cosmology University of Science and Technology of China Hefei Anhui230026 China School of Astronomy and Space Science University of Science and Technology of China Hefei Anhui230026 China Institute for the Physics and Mathematics of the Universe Kavli IPMU WPI UTIAS Tokyo Institutes for Advanced Study University of Tokyo Chiba277-8583 Japan Department of Physics National Technical University of Athens Zografou Campus GR Athens157 73 Greece

We use data from galaxy-galaxy weak lensing to perform a novel test on General Relativity (GR). In particular, we impose strong constraints using the torsional (teleparallel) formulation of gravity in which the deviation from GR is quantified by a single parameter α, an approximation which is always valid at low-redshift Universe and weak gravitational fields. We calculate the difference in the deflection angle and eventually derive the modified Excess Surface Density profile, which is mainly affected at small scales. Hence, confronting the predictions with weak lensing data from the Sloan Digital Sky Survey (SDSS) Data Release (DR) 7 we obtain the upper bound on the deviation parameter, which, expressed via the dimensional percentage in the universe energy content, reads as log10 Ω0α ≤ −18.16 ± 0.63. To our knowledge, this is the first time that GR is verified at such an accuracy at the corresponding scales. Copyright © 2019, The Authors. All rights reserved.

关键词： Relativity

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