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Magnetism and Superconductivity in the t–J Model of La_(3)Ni_(2)O_7 Under Multiband Gutzwiller Approximation

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Chinese Physics Letters 2024年第5期41卷 97-106页

作者：薛洁然王垡 International Center for quantum Materials School of PhysicsPeking UniversityBeijing 100871China Collaborative Innovation Center of quantum matter Beijing 100871China

The recent discovery of possible high temperature superconductivity in single crystals of La_(3)Ni_(2)O_(7) under pressure renews the interest in research on *** density functional theory calculations reveal that both d_(z^(2)) and d_(x^(2)-y^(2)) orbitals are active,which suggests a minimal two-orbital model to capture the low-energy physics of this *** this work,we study a bilayer two-orbital t–J model within multiband Gutzwiller approximation,and discuss the magnetism as well as the superconductivity over a wide range of the hole *** to the inter-orbital super-exchange process between d_(z^(2)) and d_(x^(2)-y^(2)) orbitals,the induced ferromagnetic coupling within layers competes with the conventional antiferromagnetic coupling,and leads to complicated hole doping dependence for the magnetic properties in the *** increasing hole doping,the system transfers to A-type antiferromagnetic state from the starting G-type antiferromagnetic(G-AFM)*** also find the inter-layer superconducting pairing of d_(x^(2)-y^(2)) orbitals dominates due to the large hopping parameter ofd_(z^(2)) along the vertical inter-layer bonds and significant Hund’s coupling between d_(z^(2)) and d_(x^(2)-y^(2)) ***,the G-AFM state and superconductivity state can coexist in the low hole doping *** take account of the pressure,we also analyze the impacts of inter-layer hopping amplitude on the system properties.

关键词： properties doping orbital

quantum phase transition of the Jaynes-Cummings model

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Science China(Physics,Mechanics & Astronomy) 2024年第1期67卷 1-9页

作者： Cheng Liu Jin-Feng Huang Key Laboratory of Low-Dimensional quantum Structures and quantum Control of Ministry of Education Key Laboratory for Matter Microstructure and Function of Hunan ProvinceDepartment of Physics and Synergetic Innovation Center for Quantum Effects and ApplicationsInstitute of Interdisciplinary StudiesHunan Normal UniversityChangsha 410081China

Herein,we propose an experimentally feasible scheme to show the quantum phase transition of the Jaynes-Cummings(JC)model by modulating the transition frequency of a two-level system in a quantum Rabi model with strong *** tuning the modulation frequency and amplitude,the ratio of the effective coupling strength of the rotating terms to the effective cavity(atomic transition)frequency can enter the deep-strong coupling regime,while the counter-rotating terms can be ***,a deep-strong JC model is *** ratio of the coupling strength to resonance frequencies in the deep-strong JC model is two orders of magnitude larger than the corresponding ratio in the original quantum Rabi *** scheme can be employed in atom-cavity resonance and off-resonance cases,and it is valid over a broad *** nonzero average cavity photons of the ground state indicate the emergence of a quantum phase ***,we demonstrate the dependence of the phase diagram on the atom-cavity detuning and modulation *** the parameters used in our scheme are within the reach of current experimental *** scheme provides a new mechanism for investigating the critical phenomena of finite-sized systems without requiring classical field limits,thereby opening a door for studying fundamental quantum phenomena occurring in the ultrastrong and even deep-strong coupling regimes.

关键词： Jaynes-Cummings model quantum phase transition frequency modulation

The medium-temperature dependence of jet transport coefficient in high-energy nucleus-nucleus collisions

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Nuclear Science and Techniques 2024年第7期35卷 173-191页

作者： Man Xie Qing-Fei Han En-Ke Wang Ben-Wei Zhang Han-Zhong Zhang Key Laboratory of Atomic and Subatomic Structure and quantum Control(MOE) Guangdong Basic Research Center of Excellence for Structure and Fundamental Interactions of MatterInstitute of Quantum Matter South China Normal UniversityGuangzhou510006China Guangdong-Hong Kong Joint Laboratory of quantum matter Guangdong Provincial Key Laboratory of Nuclear ScienceSouthern Nuclear Science Computing CenterSouth China Normal UniversityGuangzhou 510006China Key Laboratory of Quark and Lepton Physics(MOE)and institute of Particle Physics Central China Normal UniversityWuhan430079China

The medium-temperature T dependence of the jet transport coefficient̂q was studied via the nuclear modification factor RAA(p_(T))and elliptical flow parameter v_(2)(p_(T))for large transverse momentum p_(T) hadrons in high-energy nucleus-nucleus *** a next-to-leading-order perturbative QCD parton model for hard scatterings with modified fragmentation functions due to jet quenching controlled by q,we check the suppression and azimuthal anisotropy for large p_(T) hadrons,and extract q by global fits to RAA(pT)and v_(2)(pT)data in A+A collisions at RHIC and LHC,*** numerical results from the best fits show that q∕T^(3) goes down with local medium-temperature T in the parton jet *** with the case of a constant q∕T^(3),the going-down T dependence of q∕T^(3) makes a hard parton jet to lose more energy near T_(c) and therefore strengthens the azimuthal anisotropy for large pT *** a result,v_(2)(p_(T))for large pT hadrons was enhanced by approximately 10%to better fit the data at RHIC/*** the first-order phase transition from QGP to the hadron phase and the additional energy loss in the hadron phase,v_(2)(p_(T))is again enhanced by 5-10%at RHIC/LHC.

关键词： Jet quenching Jet transport parameter Hadron suppression Elliptic flow coefficient Energy loss asymmetry

Variational quantum algorithms for scanning the complex spectrum of non-Hermitian systems

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Frontiers of physics 2024年第4期19卷 275-285页

作者： Xu-Dan Xie Zheng-Yuan Xue Dan-Bo Zhang Key Laboratory of Atomic and Subatomic Structure and quantum Control(Ministry of Education) Guangdong Basic Research Center of Excellence for Structure and Fundamental Interactions of Matterand School of PhysicsSouth China Normal UniversityGuangzhou 510006China Guangdong Provincial Key Laboratory of quantum Engineering and quantum Materials Guangdong–Hong Kong Joint Laboratory of Quantum Matterand Frontier Research Institute for PhysicsSouth China Normal UniversityGuangzhou 510006China

Solving non-Hermitian quantum many-body systems on a quantum computer by minimizing the variational energy is challenging as the energy can be ***,we propose a variational quantum algorithm for solving the non-Hermitian Hamiltonian by minimizing a type of energy variance,where zero variance can naturally determine the eigenvalues and the associated left and right ***,the energy is set as a parameter in the cost function and can be tuned to scan the whole spectrum efficiently by using a two-step optimization *** numerical simulations,we demonstrate the algorithm for preparing the left and right eigenstates,verifying the biorthogonal relations,as well as evaluating the *** also investigate the impact of quantum noise on our algorithm and show that its performance can be largely improved using error mitigation ***,our work suggests an avenue for solving non-Hermitian quantum many-body systems with variational quantum algorithms on near-term noisy quantum computers.

关键词： quantum algorithm non-Hermitian physics quantum manybody systems

Simulation of optimal work extraction for quantum systems with work storage

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Chinese Physics B 2024年第2期33卷 195-203页

作者：宋鹏飞张旦波 Key Laboratory of Atomic and Subatomic Structure and quantum Control(Ministry of Education) and School of PhysicsSouth China Normal UniversityGuangzhou 510006China Guangdong Provincial Key Laboratory of quantum Engineering and quantum Materials Guangdong–Hong Kong Joint Laboratory of Quantum Matterand Frontier Research Institute for PhysicsSouth China Normal UniversityGuangzhou 510006China

The capacity to extract work from a quantum heat machine is not only of practical value but also lies at the heart of understanding quantum *** this paper,we investigate optimal work extraction for quantum systems with work storage,where extracting work is completed by a unitary evolution on the composite *** consider the physical requirement of energy conservation both strictly and on *** both,we construct their corresponding unitaries and propose variational quantum algorithms for optimal work *** show that maximal work extraction in general can be feasible when energy conservation is satisfied on *** demonstrate with numeral simulations using a continuous-variable work *** work show an implementation of a variational quantum computing approach for simulating work extraction in quantum systems.

关键词： quantum algorithm quantum thermodyanmics

Layer Hall effect induced by hidden Berry curvature in antiferromagnetic insulators

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National Science Review 2024年第2期11卷 15-23页

作者： Rui Chen Hai-Peng Sun Mingqiang Gu Chun-Bo Hua Qihang Liu Hai-Zhou Lu X.C.Xie Shenzhen institute for quantum Science and Engineering and Department of Physics Southern University of Science and Technology(SUSTech) International quantum Academy institute for Theoretical Physics and Astrophysics University of Würzburg School of Electronic and Information Engineering Hubei University of Science and Technology Guangdong Provincial Key Laboratory of Computational Science and Material Design Southern University of Science and Technology Shenzhen Key Laboratory of quantum Science and Engineering International Center for quantum Materials School of PhysicsPeking University Collaborative Innovation Center of quantum matter CAS Center for Excellence in Topological quantum Computation University of Chinese Academy of Sciences

The layer Hall effect describes electrons spontaneously deflected to opposite sides at different layers, which has been experimentally reported in the MnBi2Te4thin films under perpendicular electric fields. Here, we reveal a universal origin of the layer Hall effect in terms of the so-called hidden Berry curvature, as well as material design principles. Hence, it gives rise to zero Berry curvature in momentum space but non-zero layer-locked hidden Berry curvature in real space. We show that, compared to that of a trivial insulator, the layer Hall effect is significantly enhanced in antiferromagnetic topological insulators. Our universal picture provides a paradigm for revealing the hidden physics as a result of the interplay between the global and local symmetries, and can be generalized in various scenarios.

关键词： layerHall effect hidden Berry curvature antiferromagnetic insulator axion insulator, quantum transport

Purification of copper foils driven by single crystallization

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Chinese Physics B 2024年第2期33卷 506-511页

作者：寇金宗赵孟泽李兴光何梦林杨方友刘科海成庆秋任云龙刘灿付莹吴慕鸿刘开辉王恩哥 Songshan Lake Materials Laboratory Dongguan 523808China Beijing National Laboratory for Condensed matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China Guangdong Provincial Key Laboratory of quantum Engineering and quantum Materials School of PhysicsSouth China Normal UniversityGuangzhou 510006China Guangdong–Hong Kong Joint Laboratory of quantum matter Frontier Research Institute for PhysicsSouth China Normal UniversityGuangzhou 510006China State Key Laboratory for Mesoscopic Physics Frontiers Science Center for Nano-optoelectronicsSchool of PhysicsPeking UniversityBeijing 100871China Key Laboratory of quantum State Construction and Manipulation(Ministry of Education) Department of PhysicsRenmin University of ChinaBeijing 100872China International Center for quantum Materials Collaborative Innovation Center of Quantum MatterPeking UniversityBeijing 100871China School of Physics Liaoning UniversityShenyang 110036China

High-purity copper(Cu) with excellent thermal and electrical conductivity, is crucial in modern technological applications, including heat exchangers, integrated circuits, and superconducting magnets. The current purification process is mainly based on the zone/electrolytic refining or anion exchange, however, which excessively relies on specific integrated equipment with ultra-high vacuum or chemical solution environment, and is also bothered by external contaminants and energy consumption. Here we report a simple approach to purify the Cu foils from 99.9%(3N) to 99.99%(4N) by a temperature-gradient thermal annealing technique, accompanied by the kinetic evolution of single crystallization of *** success of purification mainly relies on(i) the segregation of elements with low effective distribution coefficient driven by grain-boundary movements and(ii) the high-temperature evaporation of elements with high saturated vapor *** purified Cu foils display higher flexibility(elongation of 70%) and electrical conductivity(104% IACS) than that of the original commercial rolled Cu foils(elongation of 10%, electrical conductivity of ~ 100% IACS). Our results provide an effective strategy to optimize the as-produced metal medium, and therefore will facilitate the potential applications of Cu foils in precision electronic products and high-frequency printed circuit boards.

关键词： purification copper foil thermal annealing technique single crystallization

Chiral bound states in a staggered array of coupled resonators

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Chinese Physics B 2024年第2期33卷 124-130页

作者：金伍林李静卢竞龚志瑞周兰 Synergetic Innovation Center for quantum Effects and Applications Key Laboratory for Matter Microstructure and Function of Hunan ProvinceKey Laboratory of Low-Dimensional Quantum Structures and Quantum Control of the Ministry of EducationSynergetic Innovation Center for Quantum Effects and ApplicationsInstitute of Interdisciplinary StudiesXiangjiang-Laboratory and Department of PhysicsHunan Normal UniversityChangsha 410081China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China

We study the chiral bound states in a coupled-resonator array with staggered hopping strengths,which interacts with a two-level small atom through a single coupling point or two adjacent *** addition to the two typical bound states found above and below the energy bands,this system presents an extraordinary chiral bound state located within the energy *** use the chirality to quantify the breaking of the mirror *** find that the chirality value undergoes continuous changes by tuning the coupling *** preferred direction of the chirality is controlled not only by the competition between the intracell and the intercell hoppings in the coupled-resonator array,but also by the coherence between the two coupling *** the case with one coupling point,the chirality values varies monotonously with difference between the intracell hopping and the intercell *** in the case with two coupling points,due to the coherence between the two coupling points the perfect chiral states can be obtained.

关键词： bound states two-level small atom coupled-resonator array chirality

Implementation of integrated nonlocal sensing for object shape and rotational speed

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 6-12页

作者： Zhenyu Guo Yunlong Wang Zehong Chang Jiawei Wang Junliang Jia Pei Zhang Ministry of Education Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed matter Shaanxi Province Key Laboratory of Quantum Information and Quantum Optoelectronic DevicesSchool of PhysicsXi’an Jiaotong UniversityXi’an 710049China

The expeditious acquisition of information pertaining to objects through the utilization of quantum technology has been a perennial issue of *** far,the efficient utilization of information from dynamic objects with limited resources remains a significant ***,we realize a nonlocal integrated sensing of the object's amplitude and phase information by combining digital spiral imaging with the correlated orbital angular momentum *** amplitude information is utilized for object identification,while the phase information enables us to determine the rotational *** demonstrate the nonlocal identification of a rotating object's shape,irrespective of its rotational symmetry,and introduce the concept of the correlated rotational Doppler effect,establishing a fundamental connection between this effect and the classical rotational Doppler effect,i.e.,that both rely on extracting crucial information from the spiral spectrum of *** present study highlights a promising pathway towards the realization of quantum remote sensing and imaging.

关键词： digital spiral imaging orbital angular momentum correlated rotational Doppler effect