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Experimental verification of generalized eigenstate thermalization hypothesis in an integrable system

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Light(Science & Applications) 2022年第7期11卷 1615-1624页

作者： Qin-Qin Wang Si-Jing Tao Wei-Wei Pan Zhe Chen Geng Chen Kai Sun Jin-Shi xu xiao-ye xu Yong-Jian Han Chuan-Feng Li Guang-Can Guo CAS Key Laboratory of Quantum Information University of Science and Technology of ChinaHefei 230026China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei 230026China Hefei National Laboratory University of Science and Technology of ChinaHefei 230088China

Identifying the general mechanics behind the equilibration of a complex isolated quantum system towards a state described by only a few parameters has been the focus of attention in non-equilibrium *** several experimentally unproven conjectures are proposed for the statistical description of quantum(non-)integrable *** plausible eigenstate thermalization hypothesis(ETH),which suggests that each energy eigenstate itself is thermal,plays a crucial role in understanding the quantum thermalization in non-integrable systems;it is commonly believed that it does not exist in integrable ***,integrable systems can still relax to the generalized Gibbs *** a microscopic perspective,understanding the origin of this generalized thermalization that occurs in an isolated integrable system is a fundamental open question lacking experimental ***,we experimentally investigated the spin subsystem relaxation in an isolated spin-orbit coupling quantum *** applying the quantum state engineering technique,we initialized the system with various distribution widths in the mutual eigenbasis of the conserved ***,we compared the steady state of the spin subsystem reached in a long-time coherent dynamics to the prediction of a generalized version of ETH and the underlying mechanism of the generalized thermalization is experimentally verified for the first *** results facilitate understanding the origin of quantum statistical mechanics.

关键词： integrable quantum state

Measuring a dynamical topological order parameter in quantum walks

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Light(Science & Applications) 2020年第1期9卷 1932-1942页

作者： xiao-ye xu Qin-Qin Wang Markus Heyl Jan Carl Budich Wei-Wei Pan Zhe Chen Munsif Jan Kai Sun Jin-Shi xu Yong-Jian Han Chuan-Feng Li Guang-Can Guo CAS Key Laboratory of Quantum Information University of Science and Technology of ChinaHefei 230026China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei 230026China Max-Planck-Institut fur Physik komplexer Systeme Nöthnitzer Straße 38D-01187 DresdenGermany Institute of Theoretical Physics Technische Universitat Dresden01062 DresdenGermany

Quantum processes of inherent dynamical nature,such as quantum walks,defy a description in terms of an equilibrium statistical physics *** now,identifying the general principles behind the underlying unitary quantum dynamics has remained a key ***,we show and experimentally observe that split-step quantum walks admit a characterization in terms of a dynamical topological order parameter(DTOP).This integer-quantized DTOP measures,at a given time,the winding of the geometric phase accumulated by the wavefunction during a quantum *** observe distinct dynamical regimes in our experimentally realized quantum walks,and each regime can be attributed to a qualitatively different temporal behavior of the *** identifying an equivalent manybody problem,we reveal an intriguing connection between the nonanalytic changes of the DTOP in quantum walks and the occurrence of dynamical quantum phase transitions.

关键词： quantum dynamical topological

Dipole–dipole interactions enhance non-Markovianity and protect information against dissipation

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Chinese Physics B 2019年第9期28卷 100-106页

作者： xiao-ye xu Qin-Qin Wang Zhe Chen Yong-Jian Han Chuan-Feng Li Guang-Can Guo Key Laboratory of Quantum Information of Chinese Academy of Sciences (CAS) University of Science and Technology of ChinaHefei 230026China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei 230026China

Preserving non-Markovianity and quantum entanglement from decoherence effect is of theoretical and practical significance in the quantum information processing *** this context, we study a system S that is initially correlated with an ancilla A, which interacts with the environment E via an amplitude damping *** also consider dipole-dipole interactions(DDIs) between the system and ancilla, which are responsible for strong *** investigate the impact of DDIs and detuning on the non-Markovianity and information exchange in different *** show that DDIs are not only better than detuning at protecting the information(without destroying the memory effect) but also induce memory by causing a transition from Markovian to non-Markovian *** contrast, although detuning also protects the information, it causes a transition from non-Markovian to the Markovian *** addition, we demonstrate that the non-Markovianity grows with increasing DDI strength and diminishes with increasing *** also show that the effects of negative detuning and DDIs can cancel out each other, causing a certain loss of coherence and information.

关键词： decoherence non-Markovianity dipole-dipole interactions entanglement

Linear optical approach to supersymmetric dynamics

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Chinese Physics B 2020年第1期29卷 300-306页

作者： Yong-Tao Zhan xiao-ye xu Qin-Qin Wang Wei-Wei Pan Munsif Jan Fu-Ming Chang Kai Sun Jin-Shi xu Yong-Jian Han Chuan-Feng Li Guang-Can Guo CAS Key Laboratory of Quantum Information University of Science and Technology of ChinaHefei 230026China Synergetic Innovation Center of Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei 230026China

The concept of supersymmetry developed in particle physics has been applied to various fields of modern *** quantum mechanics,the supersymmetric systems refer to the systems involving two supersymmetric partner Hamiltonians,whose energy levels are degeneracy except one of the systems has an extra ground state possibly,and the eigenstates of the partner systems can be mapped onto each ***,an interferometric scheme has been proposed to show this relationship in ultracold atoms[***.A 96043624(2017)].Here this approach is generalized to linear optics for observing the supersymmetric dynamics with *** time evolution operator is simulated approximately via Suzuki–Trotter expansion with considering the realization of the kinetic and potential terms *** former is realized through the diffraction nature of light and the later is implemented using a phase ***,we propose an interferometric approach which can be implemented perfectly using an amplitude alternator to realize the non-unitary *** numerical results show that our scheme is universal and can be realized with current technologies.

关键词： linear optics supersymmetry quantum simulation

Direct measurement of nonlocal wave function

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Direct measurement of nonlocal wave function

Dynamic-Disorder-Induced Enhancement of Entanglement in Photonic Quantum Walks

第十八届全国量子光学学术会议

作者：潘维韦 xiao-ye xu Chuan-Feng Li 中国科学技术大学 CAS Key Laboratory of Quantum Information University of Science and Technology of China Synergetic Innovation Center of Quantum Information and Quantum Physics University of Science and Technology of China

Entanglement and wave function description are two of the core concepts that make quantum mechanics such a unique theory. We propose a method to acquire nonlocal wave function without complicated calculation via weak values of nonlocal observables. We introduce the modular value due to obtaining the weak values of nonlocal observables requires nonlocal Hamiltonian that implies an instantaneous interaction between distant locations, which it’s hard for experiment. We show that the weak values of nonlocal observables can be yielded by using modular values of a sum of observables. For the first time, we experimentally realize the direct measurement of nonlocal wave function of two photons, which sheds new light on the direct measurement of nonlocal quantum states of bi-particle systems. Besides, extends the method to be applicable for an important scenario: the existence of nonlocal entanglement. The simplicity of the theoretical derivation, and the demonstrated feasibility of the experimental technique, can make the new method a powerful tool for studying the nature of quantum mechanics and harnessing it.

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Dynamic-Disorder-Induced Enhancement of Entanglement in Phot...

Fuzzy neural network control of underwater vehicles based on desired state programming

第十八届全国量子光学学术会议

作者：王琴琴 xiao-ye xu Chuan-Feng Li 中科大 CAS Key Laboratory of Quantum Information University of Science and Technology of China Synergetic Innovation Center of Quantum Information and Quantum Physics University of Science and Technology of China

Entanglement generation in discrete time quantum walks is deemed to be another key property beyond the transport behaviors. The latter has been widely used in investigating the localization or topology in quantum walks. How to efficiently generate such entanglement is not straightforward and only recently, it has been systematically studied in theory. Here, based on our recently developed platform with the ability of full wave function reconstruction, we perform the first experiment to study the coin-position entanglement generation and investigate the dynamics of entanglement in quantum walks. Through reconstructing the local spinor state for each site, von Neumann entropy can be obtained and used to quantify the coin-position entanglement. Comparing to the entanglement generation in the Hadamard quantum walks, we find that the enhanced entanglement in the dynamically disordered quantum walks, which is counter-intuitively, is independent of the initial state. In addition, we also study the ballistic and sub-ballistic transport behavior in the Hadmard and dynamically disordered quantum walks.

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Journal of Marine Science and Application 2006年第3期5卷 1-4页

作者： LIANG xiao LI ye xu Yu-ru WAN Lei QIN Zai-bai School of Shipbuilding Engineering Harbin Engineering University Harbin 150001 China

Due to the nonlinearity and uncertainty, the precise control of underwater vehicles in some intelligent operations hasn’t been solved very well yet. A novel method of control based on desired state programming was presented, which used the technique of fuzzy neural network. The structure of fuzzy neural network was constructed according to the moving characters and the back propagation algorithm was deduced. Simulation experiments were conducted on general detection remotely operated vehicle. The results show that there is a great improvement in response and precision over traditional control, and good robustness to the model’s uncertainty and external disturbance, which has theoretical and practical value.

关键词： underwater vehicle motion control fuzzy neural network desired state programming

The burden of upper motor neuron involvement is correlated with the bilateral limb involvement interval in patients with amyotrophic lateral sclerosis:a retrospective observational study

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Neural Regeneration Research 2025年第5期20卷 1505-1512页

作者： Jieying Wu Shan ye Xiangyi Liu Yingsheng xu Dongsheng Fan Department of Neurology Peking University Third HospitalBeijingChina Beijing Municipal Key Laboratory of Biomarker and Translational Research in Neurodegenerative Diseases BeijingChina Key Laboratory for Neuroscience National Health Commission/Ministry of EducationPeking UniversityBeijingChina

Amyotrophic lateral sclerosis is a rare neurodegenerative disease characterized by the involvement of both upper and lower motor *** bilateral limb involvement significantly affects patients'daily lives and may lead them to be confined to ***,the effect of upper and lower motor neuron impairment and other risk factors on bilateral limb involvement is *** address this issue,we retrospectively collected data from 586 amyotrophic lateral sclerosis patients with limb onset diagnosed at Peking University Third Hospital between January 2020 and May 2022.A univariate analysis revealed no significant differences in the time intervals of spread in different directions between individuals with upper motor neuron-dominant amyotrophic lateral sclerosis and those with classic amyotrophic lateral *** used causal directed acyclic graphs for risk factor determination and Cox proportional hazards models to investigate the association between the duration of bilateral limb involvement and clinical baseline characteristics in amyotrophic lateral sclerosis *** factor analyses revealed that higher upper motor neuron scores(hazard ratio[HR]=1.05,95%confidence interval[CI]=1.01–1.09,P=0.018),onset in the left limb(HR=0.72,95%CI=0.58–0.89,P=0.002),and a horizontal pattern of progression(HR=0.46,95%CI=0.37–0.58,P<0.001)were risk factors for a shorter interval until bilateral limb *** results demonstrated that a greater degree of upper motor neuron involvement might cause contralateral limb involvement to progress more quickly in limb-onset amyotrophic lateral sclerosis *** findings may improve the management of amyotrophic lateral sclerosis patients with limb onset and the prediction of patient prognosis.

关键词： amyotrophic lateral sclerosis bilateral limb involvement Cox proportional hazards regression model horizontal spread restricted cubic spline analysis time interval upper motor neuron vertical spread

Constraints on what controls millennial-scale basin-wide denudation across mountain belts, Asia

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Science China Earth Sciences 2025年第1期68卷 74-93页

作者： ye YANG Steven A.BINNIE Sheng xu Cong-Qiang LIU Tibor J.DUNAI Institute of Surface-Earth System Science School of Earth System Science Tianjin University Institute of Geology and Mineralogy University of Cologne

The terrestrial cosmogenic nuclide dataset consisting of 123310Be measurements of fluvial sediment samples across the Asian mountain belts is used to constrain the influence of climate,tectonics and topography on Earth-surface denudation processes.10Be-derived basin-wide denudation rates were recalculated using a Monte Carlo simulation approach that relied on pixel-by-pixel production *** rates derived span four orders of magnitude,from 7.4±0.7 mm kyr-1（1σ;Central Tibetan Plateau） to 9,646744+777mm kyr-1（1σ;Southern Tibetan Plateau）,with a median of 186 mm *** our results with the traditional basin-wide production rate scaling model using a centroid coordinate and mean elevation,suggests that 96.6%of production rates will be underestimated using the latter method,especially for basins with a large *** bias between both methods reaches as large as 40%,caused by basin hypsometry and the nonlinear scaling of production rate with elevation and *** of the correlations between uniformly recalculated denudation rates and tectonics,climate,topography and rock lithology will facilitate the extrapolation of denudation rates in unknown basins using available *** the perspective of local scales,precipitation coupled with neotectonics-driven landslides is likely the most influential factor in subtropical Taiwan Island,while topography primarily constrains surface denudation rates in the eastern Tibetan Plateau within a narrow range of *** highland regions with glacier coverage,such as the Pamir,central and southern Tibetan Plateau high denudation rates are affected by glaciation,whereas lower precipitation and high erosion base level may limit river incision and evolving relief in the Central Tibetan *** contrast to local-scale findings highlighting a dominant factor constraining denudation rate,our large-scale quantitative analyses across the Asian mountain belts finds that （1） topographic metrics including

关键词： 10Be-derived denudation rate Climate change Tectonic uplift Topographic gradient Asian mountains