A quantum steering ellipsoid(QSE)is a visual characterization for bipartite qubit systems,and it is also a novel avenue for describing and detecting quantum correlations.Herein,by using a QSE,we visualize and witness ...A quantum steering ellipsoid(QSE)is a visual characterization for bipartite qubit systems,and it is also a novel avenue for describing and detecting quantum correlations.Herein,by using a QSE,we visualize and witness the first-order coherence(FOC),Bell nonlocality(BN)and purity under non-inertial frames.Also,the collective influences of the depolarizing channel and the non-coherence-generating channel(NCGC)on the FOC,BN and purity are investigated in the QSE formalism.The results reveal that the distance from the center of the QSE to the center of the Bloch sphere visualizes the FOC of a bipartite system,the lengths of the QSE semiaxis visualize the BN,and the QSE's shape and position dominate the purity of the system.One can capture the FOC,BN and purity via the shape and position of the QSE in the non-inertial frame.The depolarizing channel(the NCGC)gives rise to the shrinking and degradation(the periodical oscillation)of the QSE.One can use these traits to visually characterize and detect the FOC,BN and purity under the influence of external noise.Of particular note is that the condition for the QSE to achieve the center of the Bloch sphere cannot be influenced by the depolarizing channel and the NCGC.The characterization shows that the conditions for the disappearance of the FOC are invariant under the additional influences of the depolarizing channel and NCGC.展开更多
In this work, we study the quantum steering in two-qubit Heisenberg models with Dzyaloshinskii–Moriya(DM)interaction and an external magnetic field. We find that the steerable weight(SW) and the critical temperature ...In this work, we study the quantum steering in two-qubit Heisenberg models with Dzyaloshinskii–Moriya(DM)interaction and an external magnetic field. We find that the steerable weight(SW) and the critical temperature where SW → 0 can be enhanced by the DM interactions. In the special case where the magnetic field is vanishing and the two spins are ferromagnetically coupled, the DM interaction can tune the zero-temperature SW from zero to a finite value. In addition to the SW, some other measurements used to identify the quantum entanglement and quantum correlations are investigated, i.e., the concurrence, the quantum discord, and the robustness of coherence. In the strong magnetic field limit,our results show that the SW is dramatically different from the other measurements.展开更多
We investigate the dynamical behavior of quantum steering (QS), Bell nonlocality, and entanglement in open quantum systems. We focus on a two-qubit system evolving within the framework of Kossakowski-type quantum dyna...We investigate the dynamical behavior of quantum steering (QS), Bell nonlocality, and entanglement in open quantum systems. We focus on a two-qubit system evolving within the framework of Kossakowski-type quantum dynamical semigroups. Our findings reveal that the measures of quantumness for the asymptotic states rely on the primary parameter of the quantum model. Furthermore, control over these measures can be achieved through a careful selection of these parameters. Our analysis encompasses various cases, including Bell states, Werner states, and Horodecki states, demonstrating that the asymptotic states can exhibit steering, entanglement, and Bell nonlocality. Additionally, we find that these three quantum measures of correlations can withstand the influence of the environment, maintaining their properties even over extended periods.展开更多
Various strategies have been proposed to harness and protect space-like quantum correlations in different models under decoherence.However,little attention has been given to temporal-like correlations,such as quantum ...Various strategies have been proposed to harness and protect space-like quantum correlations in different models under decoherence.However,little attention has been given to temporal-like correlations,such as quantum temporal steering(TS),in this context.In this work,we investigate TS in a frequency-modulated two-level system coupled to a zero-temperature reservoir in both the weak and strong coupling regimes.We analyze the impact of various frequency-modulated parameters on the behavior of TS and non-Markovian.The results demonstrate that appropriate frequency-modulated parameters can enhance the TS of the two-level system,regardless of whether the system is experiencing Markovian or non-Markovian dynamics.Furthermore,a suitable ratio between modulation strength and frequency(i.e.,all zeroes of the 0th Bessel function J_(0)(δ/?))can significantly enhance TS in the strong coupling regime.These findings indicate that efficient and effective manipulation of quantum TS can be achieved through a frequency-modulated approach.展开更多
We investigate the effectiveness of entropic uncertainty, entanglement and steering in discerning quantum phase transitions(QPTs). Specifically, we observe significant fluctuations in entropic uncertainty as the drivi...We investigate the effectiveness of entropic uncertainty, entanglement and steering in discerning quantum phase transitions(QPTs). Specifically, we observe significant fluctuations in entropic uncertainty as the driving parameter traverses the phase transition point. It is observed that the entropic uncertainty, entanglement and quantum steering, based on the electron distribution probability, can serve as indicators for detecting QPTs. Notably, we reveal an intriguing anticorrelation relationship between entropic uncertainty and entanglement in the Aubry–André model. Moreover, we explore the feasibility of detecting a QPT when the period parameter is a rational number. These observations open up new and efficient avenues for probing QPTs.展开更多
Quantum steering in a global state allows an observer to remotely steer a subsystem into different ensembles by performing different local measurements on the other part. We show that, in general, this property cannot...Quantum steering in a global state allows an observer to remotely steer a subsystem into different ensembles by performing different local measurements on the other part. We show that, in general, this property cannot be perfectly cloned by any joint operation between a steered subsystem and a third system. Perfect cloning is viable if and only if the initial state is of zero discord. We also investigate the process of cloning the steered qubit of a Bell state using a universal cloning machine. Einstein–Podolsky–Rosen(EPR) steering, which is a type of quantum correlation existing in the states without a local-hidden-state model, is observed in the two copy subsystems. This contradicts the conclusion of no-cloning of quantum steering(EPR steering) [C. Y. Chiu et al.,npj Quantum Inf. 2, 16020(2016)] based on a mutual information criterion for EPR steering.展开更多
Maximal steered coherence(MSC)is a noteworthy resource measure in the field of quantum information,and it is defined under the framework of coherence measure and the formalism of quantum steering ellipsoids(QSEs).Here...Maximal steered coherence(MSC)is a noteworthy resource measure in the field of quantum information,and it is defined under the framework of coherence measure and the formalism of quantum steering ellipsoids(QSEs).Here,we explore the MSC of a two-qubit X state under the common influences of reservoir and noise.The results disclose that the introduction of auxiliary qubits can give rise to enhancement of the MSC in both the strong and weak coupling regimes.Moreover,more auxiliary qubits can decrease the oscillation period of the MSC,and also suppress the oscillation amplitude of the MSC in the strong coupling regime.In contrast,the increases in auxiliary qubits result in the oscillation of the MSC for the setting of the initially weak coupling regime.Of particular interest is that the improvement effects of more auxiliary qubits on the MSC in the initially weak coupling regime are significantly stronger than that in the initially strong coupling regime.展开更多
We propose a scheme for establishing the stationary one-way quantum steering in a three-level Λ-type atomic ensemble. In our system, the cavity modes are generated from two atomic dipole-allowed transitions, which ar...We propose a scheme for establishing the stationary one-way quantum steering in a three-level Λ-type atomic ensemble. In our system, the cavity modes are generated from two atomic dipole-allowed transitions, which are in turn driven by two external classical fields. The atomic ensemble can act as an engineered reservoir to put two cavity modes into a squeezed state by two Bogoliubov dissipation pathways. When the damping rates of the two cavity modes are different,the steady-state one-way quantum steering of the intracavity and output fields is presented by adjusting the normalized detuning. The physical mechanism is analyzed based on a dressed state representation and Bogoliubov mode transformation.The achieved optical one-way quantum steering scheme has potential applications in quantum secret information sharing protocols.展开更多
A scheme is proposed to generate genuine tripartite Einstein-Podolsky-Rosen(EPR)steering in cascaded nonlinear process of the fourth-harmonic generation.The second-harmonic is generated by the first double-frequency p...A scheme is proposed to generate genuine tripartite Einstein-Podolsky-Rosen(EPR)steering in cascaded nonlinear process of the fourth-harmonic generation.The second-harmonic is generated by the first double-frequency process in an optical superlattice.Then,the fourth-harmonic is produced by the second cascaded double-frequency process through quasi-phase-matching technique in the same optical superlattice.The genuine tripartite EPR steering among the pump,the second-harmonic,and the fourth-harmonic beams can be obtained by this cascaded nonlinear process according to a criterion for genuine multipartite quantum steering.The quantum steering properties are discussed by adjusting the parameters related to the cascaded nonlinear system.The present research provides a reference scheme and data for obtaining good multipartite EPR steering in experiment and can advance the applications of quantum steering in the quantum information processing.展开更多
In the analysis of quantum discord, the minimization of average entropy traditionally involved over orthogonal projective measurements may be attained at more optimal decompositions by using the positive-operator-valu...In the analysis of quantum discord, the minimization of average entropy traditionally involved over orthogonal projective measurements may be attained at more optimal decompositions by using the positive-operator-valued measure（POVM）measurements. Taking advantage of the quantum steering ellipsoid in combination with three-element POVM optimization,we show that, for a family of two-qubit X states locally interacting with Markovian non-dissipative environments, the decay rates of quantum discord show smooth dynamical evolutions without any sudden change. This is in contrast to two-element orthogonal projective measurements, in which case the sudden change of the decay rates of quantum and classical decoherences may be a common phenomenon. Notwithstanding this, we find that a subset of X states（including the Bell diagonal states） involving POVM optimization can still preserve the sudden change character as usual.展开更多
We study the dynamics of the quantum steering between two separated qubits trapped in a one-dimensional plasmonic waveguide.By numerical methods,we calculate the quantum steerability and other quantum correlations,i.e...We study the dynamics of the quantum steering between two separated qubits trapped in a one-dimensional plasmonic waveguide.By numerical methods,we calculate the quantum steerability and other quantum correlations,i.e.,entanglement,discord,and coherence,for both cases with and without laser driving fields.It is found that steerability may exhibit a sudden disappearance and sudden reappearance phenomenon.Specifically,there exist time windows with no steerability but finite entanglement.The effects of plasmon wavenumber and the distance between the two qubits on steerability are also examined.Furthermore,we show that quantum steerability is tunable by adjusting the laser driving fields.展开更多
We aim to explore all possible scenarios of(1→2)(where one wing is untrusted and the others two wings are trusted)and(2→1)(where two wings are untrusted,and one wing is trusted)genuine tripartite Einstein-Podolsky-R...We aim to explore all possible scenarios of(1→2)(where one wing is untrusted and the others two wings are trusted)and(2→1)(where two wings are untrusted,and one wing is trusted)genuine tripartite Einstein-Podolsky-Rosen(EPR)steering.The generalized Greenberger-Horne-Zeilinger(GHZ)state is shared between three spatially separated parties,Alice,Bob and Charlie.In both(1→2)and(2→1),we discuss the untrusted party and trusted party performing a sequence of unsharp measurements,respectively.For each scenario,we deduce an upper bound on the number of sequential observers who can demonstrate genuine EPR steering through the quantum violation of tripartite steering inequality.The results show that the maximum number of observers for the generalized GHZ states can be the same with that of the maximally GHZ state in a certain range of state parameters.Moreover,both the sharpness parameters range and the state parameters range in the scenario of(1→2)steering are larger than those in the scenario of(2→1)steering.展开更多
Entanglement,quantum steering and Bell nonlocality can be used to describe the distinct quantum correlations of quantum systems.Because of their different characteristics and application fields,how to divide them quan...Entanglement,quantum steering and Bell nonlocality can be used to describe the distinct quantum correlations of quantum systems.Because of their different characteristics and application fields,how to divide them quantitatively and accurately becomes particularly important.Based on the sufficient and necessary criterion for quantum steering of an arbitrary two-qubit T-state,we derive the inequality relations between quantum steering and entanglement as well as between quantum steering and Bell nonlocality for the T-state.Additionally,we have verified those relations experimentally.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.12175001)the Natural Science Research Key Project of the Education Department of Anhui Province of China(Grant No.KJ2021A0943)+3 种基金the Research Start-up Funding Project of High Level Talent of West Anhui University(Grant No.WGKQ2021048)an Open Project of the Key Laboratory of Functional Materials and Devices for Informatics of Anhui Higher Education Institutes(Grant No.FMDI202106)the University Synergy Innovation Program of Anhui Province(Grant No.GXXT-2021-026)the Anhui Provincial Natural Science Foundation(Grant Nos.2108085MA18 and 2008085MA20)。
文摘A quantum steering ellipsoid(QSE)is a visual characterization for bipartite qubit systems,and it is also a novel avenue for describing and detecting quantum correlations.Herein,by using a QSE,we visualize and witness the first-order coherence(FOC),Bell nonlocality(BN)and purity under non-inertial frames.Also,the collective influences of the depolarizing channel and the non-coherence-generating channel(NCGC)on the FOC,BN and purity are investigated in the QSE formalism.The results reveal that the distance from the center of the QSE to the center of the Bloch sphere visualizes the FOC of a bipartite system,the lengths of the QSE semiaxis visualize the BN,and the QSE's shape and position dominate the purity of the system.One can capture the FOC,BN and purity via the shape and position of the QSE in the non-inertial frame.The depolarizing channel(the NCGC)gives rise to the shrinking and degradation(the periodical oscillation)of the QSE.One can use these traits to visually characterize and detect the FOC,BN and purity under the influence of external noise.Of particular note is that the condition for the QSE to achieve the center of the Bloch sphere cannot be influenced by the depolarizing channel and the NCGC.The characterization shows that the conditions for the disappearance of the FOC are invariant under the additional influences of the depolarizing channel and NCGC.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11504106,11805065,11247308,and 11447167)the Fundamental Research Funds for the Central Universities,China(Grant Nos.2018MS049 and 2018MS056)
文摘In this work, we study the quantum steering in two-qubit Heisenberg models with Dzyaloshinskii–Moriya(DM)interaction and an external magnetic field. We find that the steerable weight(SW) and the critical temperature where SW → 0 can be enhanced by the DM interactions. In the special case where the magnetic field is vanishing and the two spins are ferromagnetically coupled, the DM interaction can tune the zero-temperature SW from zero to a finite value. In addition to the SW, some other measurements used to identify the quantum entanglement and quantum correlations are investigated, i.e., the concurrence, the quantum discord, and the robustness of coherence. In the strong magnetic field limit,our results show that the SW is dramatically different from the other measurements.
文摘We investigate the dynamical behavior of quantum steering (QS), Bell nonlocality, and entanglement in open quantum systems. We focus on a two-qubit system evolving within the framework of Kossakowski-type quantum dynamical semigroups. Our findings reveal that the measures of quantumness for the asymptotic states rely on the primary parameter of the quantum model. Furthermore, control over these measures can be achieved through a careful selection of these parameters. Our analysis encompasses various cases, including Bell states, Werner states, and Horodecki states, demonstrating that the asymptotic states can exhibit steering, entanglement, and Bell nonlocality. Additionally, we find that these three quantum measures of correlations can withstand the influence of the environment, maintaining their properties even over extended periods.
基金Project supported by the National Natural Science Foundation of China(Grant No.62375140)。
文摘Various strategies have been proposed to harness and protect space-like quantum correlations in different models under decoherence.However,little attention has been given to temporal-like correlations,such as quantum temporal steering(TS),in this context.In this work,we investigate TS in a frequency-modulated two-level system coupled to a zero-temperature reservoir in both the weak and strong coupling regimes.We analyze the impact of various frequency-modulated parameters on the behavior of TS and non-Markovian.The results demonstrate that appropriate frequency-modulated parameters can enhance the TS of the two-level system,regardless of whether the system is experiencing Markovian or non-Markovian dynamics.Furthermore,a suitable ratio between modulation strength and frequency(i.e.,all zeroes of the 0th Bessel function J_(0)(δ/?))can significantly enhance TS in the strong coupling regime.These findings indicate that efficient and effective manipulation of quantum TS can be achieved through a frequency-modulated approach.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12075001 and 12175001)Anhui Provincial Key Research and Development Plan(Grant No.2022b13020004)the Fund of CAS Key Laboratory of Quantum Information(Grant No.KQI201701)。
文摘We investigate the effectiveness of entropic uncertainty, entanglement and steering in discerning quantum phase transitions(QPTs). Specifically, we observe significant fluctuations in entropic uncertainty as the driving parameter traverses the phase transition point. It is observed that the entropic uncertainty, entanglement and quantum steering, based on the electron distribution probability, can serve as indicators for detecting QPTs. Notably, we reveal an intriguing anticorrelation relationship between entropic uncertainty and entanglement in the Aubry–André model. Moreover, we explore the feasibility of detecting a QPT when the period parameter is a rational number. These observations open up new and efficient avenues for probing QPTs.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11675119, 11575125, and 11105097)。
文摘Quantum steering in a global state allows an observer to remotely steer a subsystem into different ensembles by performing different local measurements on the other part. We show that, in general, this property cannot be perfectly cloned by any joint operation between a steered subsystem and a third system. Perfect cloning is viable if and only if the initial state is of zero discord. We also investigate the process of cloning the steered qubit of a Bell state using a universal cloning machine. Einstein–Podolsky–Rosen(EPR) steering, which is a type of quantum correlation existing in the states without a local-hidden-state model, is observed in the two copy subsystems. This contradicts the conclusion of no-cloning of quantum steering(EPR steering) [C. Y. Chiu et al.,npj Quantum Inf. 2, 16020(2016)] based on a mutual information criterion for EPR steering.
基金supported by the National Natural Science Foundation of China(Grant No.12175001)the Key Project of Natural Science Research of West Anhui University(Grant No.WXZR202311)+4 种基金the Open Fund of Anhui Undergrowth Crop Intelligent Equipment Engineering Research Center(Grant No.AUCIEERC-2022-01)Anhui Undergrowth Crop Intelligent Equipment Engineering Research Center(Grant No.2022AH010091)the Natural Science Research Key Project of Education Department of Anhui Province of China(Grant No.2023AH052648)the University Synergy Innovation Program of Anhui Province(Grant No.GXXT-2021-026)the Anhui Provincial Natural Science Foundation(Grant Nos.2108085MA18 and 2008085MA20).
文摘Maximal steered coherence(MSC)is a noteworthy resource measure in the field of quantum information,and it is defined under the framework of coherence measure and the formalism of quantum steering ellipsoids(QSEs).Here,we explore the MSC of a two-qubit X state under the common influences of reservoir and noise.The results disclose that the introduction of auxiliary qubits can give rise to enhancement of the MSC in both the strong and weak coupling regimes.Moreover,more auxiliary qubits can decrease the oscillation period of the MSC,and also suppress the oscillation amplitude of the MSC in the strong coupling regime.In contrast,the increases in auxiliary qubits result in the oscillation of the MSC for the setting of the initially weak coupling regime.Of particular interest is that the improvement effects of more auxiliary qubits on the MSC in the initially weak coupling regime are significantly stronger than that in the initially strong coupling regime.
基金Project supported by Wuhan Donghu University Youth Foundation of Natural science (Grant No. 2022dhzk009)。
文摘We propose a scheme for establishing the stationary one-way quantum steering in a three-level Λ-type atomic ensemble. In our system, the cavity modes are generated from two atomic dipole-allowed transitions, which are in turn driven by two external classical fields. The atomic ensemble can act as an engineered reservoir to put two cavity modes into a squeezed state by two Bogoliubov dissipation pathways. When the damping rates of the two cavity modes are different,the steady-state one-way quantum steering of the intracavity and output fields is presented by adjusting the normalized detuning. The physical mechanism is analyzed based on a dressed state representation and Bogoliubov mode transformation.The achieved optical one-way quantum steering scheme has potential applications in quantum secret information sharing protocols.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61975184,91636108,and 61775043)the Natural Science Foundation of Zhejiang Province,China(Grant No.LY18A040007)+1 种基金the Science Foundation of Zhejiang Sci-Tech University(Grant Nos.19062151-Y and 18062145-Y)the Open Foundation of the Key Laboratory of Optical Field Manipulation of Zhejiang Province,China(Grant No.ZJOFM-2019-002).
文摘A scheme is proposed to generate genuine tripartite Einstein-Podolsky-Rosen(EPR)steering in cascaded nonlinear process of the fourth-harmonic generation.The second-harmonic is generated by the first double-frequency process in an optical superlattice.Then,the fourth-harmonic is produced by the second cascaded double-frequency process through quasi-phase-matching technique in the same optical superlattice.The genuine tripartite EPR steering among the pump,the second-harmonic,and the fourth-harmonic beams can be obtained by this cascaded nonlinear process according to a criterion for genuine multipartite quantum steering.The quantum steering properties are discussed by adjusting the parameters related to the cascaded nonlinear system.The present research provides a reference scheme and data for obtaining good multipartite EPR steering in experiment and can advance the applications of quantum steering in the quantum information processing.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11305074,11135002,and 11275083)
文摘In the analysis of quantum discord, the minimization of average entropy traditionally involved over orthogonal projective measurements may be attained at more optimal decompositions by using the positive-operator-valued measure（POVM）measurements. Taking advantage of the quantum steering ellipsoid in combination with three-element POVM optimization,we show that, for a family of two-qubit X states locally interacting with Markovian non-dissipative environments, the decay rates of quantum discord show smooth dynamical evolutions without any sudden change. This is in contrast to two-element orthogonal projective measurements, in which case the sudden change of the decay rates of quantum and classical decoherences may be a common phenomenon. Notwithstanding this, we find that a subset of X states（including the Bell diagonal states） involving POVM optimization can still preserve the sudden change character as usual.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51876059 and 11805065)the Fundamental Research Funds for the Central Universities(Grant Nos.2021MS009 and 2021MS046)
文摘We study the dynamics of the quantum steering between two separated qubits trapped in a one-dimensional plasmonic waveguide.By numerical methods,we calculate the quantum steerability and other quantum correlations,i.e.,entanglement,discord,and coherence,for both cases with and without laser driving fields.It is found that steerability may exhibit a sudden disappearance and sudden reappearance phenomenon.Specifically,there exist time windows with no steerability but finite entanglement.The effects of plasmon wavenumber and the distance between the two qubits on steerability are also examined.Furthermore,we show that quantum steerability is tunable by adjusting the laser driving fields.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.62171056 and 61973021)Henan Key Laboratory of Network Cryptography Technology(Grant No.LNCT2022-A03)。
文摘We aim to explore all possible scenarios of(1→2)(where one wing is untrusted and the others two wings are trusted)and(2→1)(where two wings are untrusted,and one wing is trusted)genuine tripartite Einstein-Podolsky-Rosen(EPR)steering.The generalized Greenberger-Horne-Zeilinger(GHZ)state is shared between three spatially separated parties,Alice,Bob and Charlie.In both(1→2)and(2→1),we discuss the untrusted party and trusted party performing a sequence of unsharp measurements,respectively.For each scenario,we deduce an upper bound on the number of sequential observers who can demonstrate genuine EPR steering through the quantum violation of tripartite steering inequality.The results show that the maximum number of observers for the generalized GHZ states can be the same with that of the maximally GHZ state in a certain range of state parameters.Moreover,both the sharpness parameters range and the state parameters range in the scenario of(1→2)steering are larger than those in the scenario of(2→1)steering.
基金the National Natural Science Foundation of China(Grant Nos.12175001 and 12075001).
文摘Entanglement,quantum steering and Bell nonlocality can be used to describe the distinct quantum correlations of quantum systems.Because of their different characteristics and application fields,how to divide them quantitatively and accurately becomes particularly important.Based on the sufficient and necessary criterion for quantum steering of an arbitrary two-qubit T-state,we derive the inequality relations between quantum steering and entanglement as well as between quantum steering and Bell nonlocality for the T-state.Additionally,we have verified those relations experimentally.
