The Dicke model,which describes the collective interaction between an ensemble of atoms and a single-mode photon field,serves as a fundamental framework for studying light-matter interactions and quantum electrodynami...The Dicke model,which describes the collective interaction between an ensemble of atoms and a single-mode photon field,serves as a fundamental framework for studying light-matter interactions and quantum electrodynamic phenomena.In this work,we investigate the manifestation of non-Hermitian effects in a generalized Dicke model,where two dissipative atom ensembles interact with a single-mode photon field.We explore the system in the semiclassical limit as a non-Hermitian Dicke model,revealing rich exceptional points(EPs)and diabolic points.Furthermore,we explore the quantum signature of EPs in the Hilbert space,relying on discrete photon numbers.The transition of photons from antibunching to bunching at steady state is unravelled.Our findings deepen the understanding of non-Hermitian physics in light-matter interaction,which is instructive for the design of advanced photonic devices.展开更多
The anisotropic Dicke model offers a platform for the exploration of numerous quantum many-body phenomena.Here,we propose a Floquet-engineered scheme to realize such a system with strong dipole-dipole interactions usi...The anisotropic Dicke model offers a platform for the exploration of numerous quantum many-body phenomena.Here,we propose a Floquet-engineered scheme to realize such a system with strong dipole-dipole interactions using Rydberg atom arrays in an optical cavity.By periodically modulating the microwave fields,the anisotropic parameter can be precisely controlled and tuned between zero and one,enabling the system to transition smoothly from being purely dominated by rotating-wave terms to being exclusively governed by counter-rotating wave excitations.Leveraging this tunability,we demonstrate enhanced preparation of adiabatic superradiant and superradiant solid phases where symmetryprotected energy gaps suppress undesired level crossings.Our approach,combining Rydberg interactions and cavitymediated long-range correlations,establishes a versatile framework for the quantum simulation of light-matter interactions and the exploration of exotic many-body phases.展开更多
Quantum quenches in the Dicke model were studied both in the thermodynamic limit and the finite systems.For the integrable situation in the thermodynamic limit,the generalized Gibbs ensemble can effectively describe t...Quantum quenches in the Dicke model were studied both in the thermodynamic limit and the finite systems.For the integrable situation in the thermodynamic limit,the generalized Gibbs ensemble can effectively describe the energylevel occupations for the quench within the normal phase,but it fails for the quench to the superradiant phase.For the finite systems which are considered non-integrable,the post quench systems were studied by comparing with the thermal ensembles.The canonical ensembles are directly available for the quench within the normal phase.With the increasing of the target coupling strength over the equilibrium phase transition critical point,sudden changes take place for the effective temperature and the distance to the thermal ensembles.The thermalization was also studied by comparing with the results of the microcanonical ensembles.展开更多
Out-of-time-ordered correlation(OTOC)functions have been used as an indicator of quantum chaos in a lot of physical systems.In this work,we numerically demonstrate that zero temperature OTOC can detect quantum phase t...Out-of-time-ordered correlation(OTOC)functions have been used as an indicator of quantum chaos in a lot of physical systems.In this work,we numerically demonstrate that zero temperature OTOC can detect quantum phase transition in the anisotropic Dicke model.The phase diagram is given with OTOC.The finite-size effect is studied.Finally,the temperature effect is discussed.展开更多
Despite the efforts by Ministry of Education to promote Information and Communication Technology （ICT） in education in Malaysia, the Islamic education syllabus is far behind the intended plan in ICT usage in learnin...Despite the efforts by Ministry of Education to promote Information and Communication Technology （ICT） in education in Malaysia, the Islamic education syllabus is far behind the intended plan in ICT usage in learning and teaching. Concern was raised that Islamic Studies faced the risk of being misunderstood if the lessons were taught through self-accessing method with minimal intervention from teachers. Using the Dick and Carey instructional model as a framework, an e-learning version was devised for the national Form 4 Islamic Studies syllabus, ＂The steps and procedures of Hajj and Umrah＂. The Islamic Studies textbook for national secondary schools in Malaysia was reviewed using a systematic approach, from identifying the instructional goal through to formative and summative evaluation processes. Interview sessions with students were conducted to assess the developed e-learning Islamic Studies content. A subsequent survey with students was conducted. Results from the study indicated the e-learning Islamic Studies content had the potential to help students, being easy to use, and attracting and retaining students＇ attention.展开更多
The existence of quantum tricriticality and exotic phases are found in a tricritical Dicke triangle(TDT)where three cavities,each one containing an ensemble of three-level atoms,are connected to each other through the...The existence of quantum tricriticality and exotic phases are found in a tricritical Dicke triangle(TDT)where three cavities,each one containing an ensemble of three-level atoms,are connected to each other through the action of an artificial magnetic field.The conventional superradiant phase(SR)is connected to the normal phase through firstand second-order boundaries,with tricritical points located at the intersection of such boundaries.Apart from the SR phase,a chiral superradiant(CSR)phase is found by tuning the artificial magnetic field.This phase is characterized by a nonzero photon current and its boundary presents chiral tricritical points(CTCPs).Through the study of different critical exponents,we are able to differentiate the universality class of the CTCP and TCP from that of second-order critical points,as well as find distinctive critical behavior among the two different superradiant phases.The TDT can be implemented in various systems,including atoms in optical cavities as well as the circuit QED system,allowing the exploration of a great variety of critical manifolds.展开更多
基金supported by the National Key R&D Program of China(Grant No.2022YFA1404400)the National Natural Science Foundation of China(Grant Nos.12125504 and 12305050)+3 种基金Zhejiang Provincial Natural Science Foundation(Grant No.LZ25A050001)the Doctoral Support Program for Young Talents of the China Association for Science and Technologythe Hundred Talents Program of the Chinese Academy of Sciencesthe Natural Science Foundation of Jiangsu Higher Education Institutions of China(Grant No.23KJB140017)。
文摘The Dicke model,which describes the collective interaction between an ensemble of atoms and a single-mode photon field,serves as a fundamental framework for studying light-matter interactions and quantum electrodynamic phenomena.In this work,we investigate the manifestation of non-Hermitian effects in a generalized Dicke model,where two dissipative atom ensembles interact with a single-mode photon field.We explore the system in the semiclassical limit as a non-Hermitian Dicke model,revealing rich exceptional points(EPs)and diabolic points.Furthermore,we explore the quantum signature of EPs in the Hilbert space,relying on discrete photon numbers.The transition of photons from antibunching to bunching at steady state is unravelled.Our findings deepen the understanding of non-Hermitian physics in light-matter interaction,which is instructive for the design of advanced photonic devices.
基金supported by the National Natural Science Foundation of China(Grant No.12274045)the National Natural Science Foundation of China(Grant No.12347101)the Program of the State Key Laboratory of Quantum Optics and Quantum Optics Devices(Grant No.KF202211).
文摘The anisotropic Dicke model offers a platform for the exploration of numerous quantum many-body phenomena.Here,we propose a Floquet-engineered scheme to realize such a system with strong dipole-dipole interactions using Rydberg atom arrays in an optical cavity.By periodically modulating the microwave fields,the anisotropic parameter can be precisely controlled and tuned between zero and one,enabling the system to transition smoothly from being purely dominated by rotating-wave terms to being exclusively governed by counter-rotating wave excitations.Leveraging this tunability,we demonstrate enhanced preparation of adiabatic superradiant and superradiant solid phases where symmetryprotected energy gaps suppress undesired level crossings.Our approach,combining Rydberg interactions and cavitymediated long-range correlations,establishes a versatile framework for the quantum simulation of light-matter interactions and the exploration of exotic many-body phases.
基金Project supported by the National Natural Science Foundation of China(Grant No.11147110)the Natural Science Youth Foundation of Shanxi,China(Grant No.2011021003)。
文摘Quantum quenches in the Dicke model were studied both in the thermodynamic limit and the finite systems.For the integrable situation in the thermodynamic limit,the generalized Gibbs ensemble can effectively describe the energylevel occupations for the quench within the normal phase,but it fails for the quench to the superradiant phase.For the finite systems which are considered non-integrable,the post quench systems were studied by comparing with the thermal ensembles.The canonical ensembles are directly available for the quench within the normal phase.With the increasing of the target coupling strength over the equilibrium phase transition critical point,sudden changes take place for the effective temperature and the distance to the thermal ensembles.The thermalization was also studied by comparing with the results of the microcanonical ensembles.
文摘Out-of-time-ordered correlation(OTOC)functions have been used as an indicator of quantum chaos in a lot of physical systems.In this work,we numerically demonstrate that zero temperature OTOC can detect quantum phase transition in the anisotropic Dicke model.The phase diagram is given with OTOC.The finite-size effect is studied.Finally,the temperature effect is discussed.
文摘Despite the efforts by Ministry of Education to promote Information and Communication Technology （ICT） in education in Malaysia, the Islamic education syllabus is far behind the intended plan in ICT usage in learning and teaching. Concern was raised that Islamic Studies faced the risk of being misunderstood if the lessons were taught through self-accessing method with minimal intervention from teachers. Using the Dick and Carey instructional model as a framework, an e-learning version was devised for the national Form 4 Islamic Studies syllabus, ＂The steps and procedures of Hajj and Umrah＂. The Islamic Studies textbook for national secondary schools in Malaysia was reviewed using a systematic approach, from identifying the instructional goal through to formative and summative evaluation processes. Interview sessions with students were conducted to assess the developed e-learning Islamic Studies content. A subsequent survey with students was conducted. Results from the study indicated the e-learning Islamic Studies content had the potential to help students, being easy to use, and attracting and retaining students＇ attention.
基金supported by NSFC under Grant No.12075040 and No.12147102Chongqing NSF under Grants No.cstc2020jcyj-msxmX0890+2 种基金Fundamental Research Funds for the Central Universities Grant No.2021CDJQY-007support from the US NSF(Grant No.PHY-2207283)the Welch Foundatioin(Grant No.C-1669).
文摘The existence of quantum tricriticality and exotic phases are found in a tricritical Dicke triangle(TDT)where three cavities,each one containing an ensemble of three-level atoms,are connected to each other through the action of an artificial magnetic field.The conventional superradiant phase(SR)is connected to the normal phase through firstand second-order boundaries,with tricritical points located at the intersection of such boundaries.Apart from the SR phase,a chiral superradiant(CSR)phase is found by tuning the artificial magnetic field.This phase is characterized by a nonzero photon current and its boundary presents chiral tricritical points(CTCPs).Through the study of different critical exponents,we are able to differentiate the universality class of the CTCP and TCP from that of second-order critical points,as well as find distinctive critical behavior among the two different superradiant phases.The TDT can be implemented in various systems,including atoms in optical cavities as well as the circuit QED system,allowing the exploration of a great variety of critical manifolds.
