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
In a recent paper [Phys. Rev. A 76 042313 （2007）], Sainz and Bjork introduced an entanglement invariant ε under evolution for a system of four qubits interacting through two isolated Jaynes-Cummings Hamiltonians. T...In a recent paper [Phys. Rev. A 76 042313 （2007）], Sainz and Bjork introduced an entanglement invariant ε under evolution for a system of four qubits interacting through two isolated Jaynes-Cummings Hamiltonians. This paper proves that this entanglement invariant ε is closely connected with the linear entropy between two independent subsystems.展开更多
In this paper, we consider the entanglement dynamics of a four-qubit model [2006 Phys. Rev. A 74 042328] where two entangled qubits a and b locally interact with separate qubits A and B via the spin-exchange-like Hami...In this paper, we consider the entanglement dynamics of a four-qubit model [2006 Phys. Rev. A 74 042328] where two entangled qubits a and b locally interact with separate qubits A and B via the spin-exchange-like Hamiltonian. We study the effect of purity of initial entangled state of qubits a, b on the entanglement evolution and its relation with energy transfer. Also, we find that the total bipartite entanglement of qubits a, b plus A, B is not a constant any longer when the initial entangled state of a, b is not pure, which is a complement to the result in the paper [2007 J. Phys. B 40 S45] for the pure case.展开更多
Ultrafast diffraction with free attosecond electron pulses promises insight into the four-dimensional motion of charge density inatoms,molecules and condensed matter. Here we consider the quantum dynamics of the elect...Ultrafast diffraction with free attosecond electron pulses promises insight into the four-dimensional motion of charge density inatoms,molecules and condensed matter. Here we consider the quantum dynamics of the electron-electron scattering process on anattosecond time scale. By numerically solving the time-dependent two-electron Schrdinger equation,we investigate the interactionof an incoming keV-range electron wavepacket by the bound electron of an aligned H+2 molecule,using a one-dimensional model.Our findings reveal the ratio of elastic to inelastic contributions,the role of exchange interaction,and the influence of the molecularelectron density to diffraction. Momentum transfer during the scattering process,from the incoming to the bound electron mediatedby the nuclei,leaves the bound electron in a state of coherent oscillation with attosecond recurrences. Entanglement causes relatedstate-selective oscillations in the phase shift of the scattered electron. Two scenarios of distinguishable and indistinguishable freeand bound electrons yield equivalent results,irrespective of the electronic spins. This suggests to employ the scenario of distinguishable electrons,which is computationally less demanding. Our findings support the possibility of using electron diffraction forimaging the motion of charge density,but also suggest the application of free electron pulses for inducing attosecond dynamics.展开更多
We investigate the entanglement dynamics via the concurrence of two distant atoms interacting off-resonantly with two cavity fields in Fock states, respectively. We find that the evolution of entanglement has sudden d...We investigate the entanglement dynamics via the concurrence of two distant atoms interacting off-resonantly with two cavity fields in Fock states, respectively. We find that the evolution of entanglement has sudden death and sudden birth phenomena, that with the increase of photon numbers in the two cavities, the alternate frequency of sudden death and sudden birth turns fast, and that the amplitude of concurrence oscillates regularly with oscillation frequency becoming slow when the cavity fields have the same photon numbers. While, the maximum of concurrence declines and the amplitude of concurrence oscillates irregularly when the two cavity fields have different photon numbers. In addition, we find the length of death time is dependent on the initial entanglement.展开更多
The entanglement dynamics of a two-qutrit system under decoherence from a spin environment is investigated by using negativityas entanglement measure. Our results imply that the entanglement evolution depends not only...The entanglement dynamics of a two-qutrit system under decoherence from a spin environment is investigated by using negativityas entanglement measure. Our results imply that the entanglement evolution depends not only on the coupling strength and thetunneling elements of the environment but also on the number of the freedom degrees and the initial state of the environment.展开更多
In polymer physics,the concept of entanglement refers to the topological constraints between long polymer chains that are closely packed together.Both theory and experimentation suggest that entanglement has a signifi...In polymer physics,the concept of entanglement refers to the topological constraints between long polymer chains that are closely packed together.Both theory and experimentation suggest that entanglement has a significant influence on the mechanical properties of polymers.This indicates its promise for materials design across various applications.However,understanding the relationship between entanglement and mechanical properties is complex,especially due to challenges related to length scale constraints and the diffculties of direct experimental observation.This research delves into how the polymer network structure changes when deformed.We specifically examine the relationship between entanglement,crosslinked networks,and their roles in stretching both entangled and unentangled polymer systems.For unentangled polymers,our findings underscore the pivotal role of crosslinking bond strength in determining the system's overall strength and resistance to deformation.As for entangled polymers,entanglement plays a pivotal role in load bearing during the initial stretching stage,preserving the integrity of the polymer network.As the stretching continues and entanglement diminishes,the responsibility for bearing the load increasingly shifts to the crosslinking network,signifying a critical change in the system's behavior.We noted a linear correlation between the increase in entanglement and the rise in tensile stress during the initial stretching stage.Conversely,the destruction of the network correlates with a decrease in tensile stress in the later stage.The findings provide vital insights into the complex dynamics between entanglement and crosslinking in the stretching processes of polymer networks,offering valuable guidance for future manipulation and design of polymer materials to achieve desired'mechanical properties.展开更多
In the measurement-based model of quantum computing, a one-way quantum computer consisting of many qubits can be immersed in a common environment as a simple decoherence mechanism. This paper studies the dynamics of e...In the measurement-based model of quantum computing, a one-way quantum computer consisting of many qubits can be immersed in a common environment as a simple decoherence mechanism. This paper studies the dynamics of entanglement witness for 3-qubit cluster states in the common environment. The result shows that environment can induce an interesting feature in the time evolution of the entanglement witness： i.e., the periodical collapse and revival of the entanglement dynamics.展开更多
We investigate the time evolution of entanglement between two quantum dots in an engineered vacuum environment such that a metallic nanoring having a surface plasmon is placed near the quantum dots. Such engineering i...We investigate the time evolution of entanglement between two quantum dots in an engineered vacuum environment such that a metallic nanoring having a surface plasmon is placed near the quantum dots. Such engineering in environment results in oscillations in entanglement dynamics of the quantum dots systems. With proper adjustment of the separation between the quantum dots, entanglement decay can be stabilized and preserved for longer time than its decay without the surface plasmons interactions.展开更多
By preparing homogenous blend samples with different degrees of chain entanglement, we report an anomalous contribution of chain entanglement to phase separation temperature and rate of poly（methyl methacrylate）/pol...By preparing homogenous blend samples with different degrees of chain entanglement, we report an anomalous contribution of chain entanglement to phase separation temperature and rate of poly（methyl methacrylate）/poly（styrene-co- maleic anhydride） （PMMA/SMA） blends presenting a typical lower critical solution temperature （LCST） behavior. The melt- mixed PMMA/SMA blends with a higher chain entanglement density present a lower cloud point （To） and shorter delay time, but lower phase separation rate at the given temperature than solution-cast ones, suggesting that for the polymer blends with different condensed state structure, thermodynamically more facilitation to phase separation （lower Tc） is not necessarily equivalent to faster kinetics （decomposition rate）. The experimental results indicate that the lower Tc of melt-mixed sample is ascribed to smaller concentration fluctuation wavelength （Am） induced by higher entanglement degree, while higher entanglement degree in melt-mixed sample leads to a confined segmental dynamics and consequently a slower kinetics （decomposition rate） dominated by macromolecular diffusion at a comparable quench depth. These results reveal that the chain packing in polymer blends can remarkably influence the liquid-liquid phase separation behavior, which is a significant difference from decomposition of small molecular mixtures.展开更多
Considering the dipole-dipole coupling intensity between two atoms and the field in the Fock state, the entanglement dynamics between two atoms that are initially entangled in the system of two two-level atoms coupled...Considering the dipole-dipole coupling intensity between two atoms and the field in the Fock state, the entanglement dynamics between two atoms that are initially entangled in the system of two two-level atoms coupled to a single mode cavity in the presence of phase decoherence has been investigated. The two-atom entanglement appears with periodicity without considering phase decoherence, however, the phase decoherence causes the decay of entanglement between two atoms, with the increasing of the phase decoherence coefficient, the entanglement will quickly become a constant value, which is affected by the two-atom initial state. Meanwhile the two-atom quantum state will forever stay in the maximal entangled state when the initial state is proper even in the presence of phase decoherence. On the other hand, the Bell violation and the entanglement do not satisfy the monotonous relation, a large Bell violation implies the presence of a large amount of entanglement under certain conditions, while a large Bell violation corresponds to a little amount of entanglement in certain situations. However, the violation of Bell-CHSH inequality can reach the maximal value if two atoms are in the maximal entangled state, or vice versa.展开更多
We propose a novel scheme for generating the entanglement of two oscillating mirrors in an optomechanical system via a flying atom. In this scheme, a two-level atom, in an arbitrary superposition state, passes through...We propose a novel scheme for generating the entanglement of two oscillating mirrors in an optomechanical system via a flying atom. In this scheme, a two-level atom, in an arbitrary superposition state, passes through an optomechanical system with two oscillating cavity-mirrors, and then its states are detected. In this way, we can generate the entangled states of the two oscillating mirrors. We derive the analytical expressions of the entangled states and make numerical calculations. We find that the entanglement of the two oscillating mirrors can be controlled by the initial state of the atom, the optomechanical coupling strength, and the coupling strength between the atom and the cavity field. We investigate the dynamics of the system with dissipations and discuss the experimental feasibility.展开更多
In this study, we investigate the phenomenon of distillability sudden death （DSD） for a two-qutrit system coupled to an XY spin chain. In virtue of the negativity and realignment criterion, we show that certain init...In this study, we investigate the phenomenon of distillability sudden death （DSD） for a two-qutrit system coupled to an XY spin chain. In virtue of the negativity and realignment criterion, we show that certain initial-prepared free entangled states may become bound entangled states in a finite time. The possibility of a DSD not only depends on the initial state parameter, but is also determined by the coupling between the two-qutrit system and the spin chain. The effects of other parameters related with the system and the spin chain （e.g., the total number of spins in the spin chain, strengths of the transverse field, and anisotropy parameter） on the time-determined bound entangled state are also investigated in detail. Accordingly, some effective methods of controlling the DSD are proposed.展开更多
In this paper,we have investigated the quantum entanglement of quantum states undergoing decoherence from a spin environment which drives a quantum phase transition.From our analysis,we find that the entanglement dyna...In this paper,we have investigated the quantum entanglement of quantum states undergoing decoherence from a spin environment which drives a quantum phase transition.From our analysis,we find that the entanglement dynamics depends not only on the coupling strength but also on the external magnetic field and the number of the freedom degrees of the environment.Specially,our results imply that the decay of the entanglement can be enhanced by the quantum phase transition of the environment when the system is coupled to the environment weakly.Additionally,the discussion of the case of the multipartite states with high dimensions is made.展开更多
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 10774088)
文摘In a recent paper [Phys. Rev. A 76 042313 （2007）], Sainz and Bjork introduced an entanglement invariant ε under evolution for a system of four qubits interacting through two isolated Jaynes-Cummings Hamiltonians. This paper proves that this entanglement invariant ε is closely connected with the linear entropy between two independent subsystems.
基金supported by National Natural Science Foundation of China (Grant No 10774088)
文摘In this paper, we consider the entanglement dynamics of a four-qubit model [2006 Phys. Rev. A 74 042328] where two entangled qubits a and b locally interact with separate qubits A and B via the spin-exchange-like Hamiltonian. We study the effect of purity of initial entangled state of qubits a, b on the entanglement evolution and its relation with energy transfer. Also, we find that the total bipartite entanglement of qubits a, b plus A, B is not a constant any longer when the initial entangled state of a, b is not pure, which is a complement to the result in the paper [2007 J. Phys. B 40 S45] for the pure case.
基金support by the Rudolf-Kaiser-Stiftung and the Munich Centre for Advanced Photonics as well as by Deutsche Forschungs-gemeinschaft (Grant No.Sfb450TPC1)
文摘Ultrafast diffraction with free attosecond electron pulses promises insight into the four-dimensional motion of charge density inatoms,molecules and condensed matter. Here we consider the quantum dynamics of the electron-electron scattering process on anattosecond time scale. By numerically solving the time-dependent two-electron Schrdinger equation,we investigate the interactionof an incoming keV-range electron wavepacket by the bound electron of an aligned H+2 molecule,using a one-dimensional model.Our findings reveal the ratio of elastic to inelastic contributions,the role of exchange interaction,and the influence of the molecularelectron density to diffraction. Momentum transfer during the scattering process,from the incoming to the bound electron mediatedby the nuclei,leaves the bound electron in a state of coherent oscillation with attosecond recurrences. Entanglement causes relatedstate-selective oscillations in the phase shift of the scattered electron. Two scenarios of distinguishable and indistinguishable freeand bound electrons yield equivalent results,irrespective of the electronic spins. This suggests to employ the scenario of distinguishable electrons,which is computationally less demanding. Our findings support the possibility of using electron diffraction forimaging the motion of charge density,but also suggest the application of free electron pulses for inducing attosecond dynamics.
基金Project supported by the National Natural Science Foundation of China (Grant No. 60667001)
文摘We investigate the entanglement dynamics via the concurrence of two distant atoms interacting off-resonantly with two cavity fields in Fock states, respectively. We find that the evolution of entanglement has sudden death and sudden birth phenomena, that with the increase of photon numbers in the two cavities, the alternate frequency of sudden death and sudden birth turns fast, and that the amplitude of concurrence oscillates regularly with oscillation frequency becoming slow when the cavity fields have the same photon numbers. While, the maximum of concurrence declines and the amplitude of concurrence oscillates irregularly when the two cavity fields have different photon numbers. In addition, we find the length of death time is dependent on the initial entanglement.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10947115, 10975125 and 11004001)
文摘The entanglement dynamics of a two-qutrit system under decoherence from a spin environment is investigated by using negativityas entanglement measure. Our results imply that the entanglement evolution depends not only on the coupling strength and thetunneling elements of the environment but also on the number of the freedom degrees and the initial state of the environment.
基金Y.L.gratefully acknowledges financial support from the U.S.National Science Foundation(CMMI-2314424,CMMI-2316200,and CAREER Award CMMI-2323108)and 3 M's Non-Tenured Faculty AwardSupport for this research was also provided by the University of Wisconsin-Madison,Office of the Vice Chancellor for Research and Graduate Education with funding from the Wisconsin Alumni Research Foundation.
文摘In polymer physics,the concept of entanglement refers to the topological constraints between long polymer chains that are closely packed together.Both theory and experimentation suggest that entanglement has a significant influence on the mechanical properties of polymers.This indicates its promise for materials design across various applications.However,understanding the relationship between entanglement and mechanical properties is complex,especially due to challenges related to length scale constraints and the diffculties of direct experimental observation.This research delves into how the polymer network structure changes when deformed.We specifically examine the relationship between entanglement,crosslinked networks,and their roles in stretching both entangled and unentangled polymer systems.For unentangled polymers,our findings underscore the pivotal role of crosslinking bond strength in determining the system's overall strength and resistance to deformation.As for entangled polymers,entanglement plays a pivotal role in load bearing during the initial stretching stage,preserving the integrity of the polymer network.As the stretching continues and entanglement diminishes,the responsibility for bearing the load increasingly shifts to the crosslinking network,signifying a critical change in the system's behavior.We noted a linear correlation between the increase in entanglement and the rise in tensile stress during the initial stretching stage.Conversely,the destruction of the network correlates with a decrease in tensile stress in the later stage.The findings provide vital insights into the complex dynamics between entanglement and crosslinking in the stretching processes of polymer networks,offering valuable guidance for future manipulation and design of polymer materials to achieve desired'mechanical properties.
基金Project supported by the Natural Science Foundation of Shandong Province, China （Grant No Y2006 A05）.
文摘In the measurement-based model of quantum computing, a one-way quantum computer consisting of many qubits can be immersed in a common environment as a simple decoherence mechanism. This paper studies the dynamics of entanglement witness for 3-qubit cluster states in the common environment. The result shows that environment can induce an interesting feature in the time evolution of the entanglement witness： i.e., the periodical collapse and revival of the entanglement dynamics.
基金supported by the National Natural Science Foundation of China(Grant Nos.11274132 and 11550110180)
文摘We investigate the time evolution of entanglement between two quantum dots in an engineered vacuum environment such that a metallic nanoring having a surface plasmon is placed near the quantum dots. Such engineering in environment results in oscillations in entanglement dynamics of the quantum dots systems. With proper adjustment of the separation between the quantum dots, entanglement decay can be stabilized and preserved for longer time than its decay without the surface plasmons interactions.
基金financially supported by the National Natural Science Foundation of China(No.51173165)the Fundamental Research Funds for the Central Universities(No.2013QNA4048)
文摘By preparing homogenous blend samples with different degrees of chain entanglement, we report an anomalous contribution of chain entanglement to phase separation temperature and rate of poly（methyl methacrylate）/poly（styrene-co- maleic anhydride） （PMMA/SMA） blends presenting a typical lower critical solution temperature （LCST） behavior. The melt- mixed PMMA/SMA blends with a higher chain entanglement density present a lower cloud point （To） and shorter delay time, but lower phase separation rate at the given temperature than solution-cast ones, suggesting that for the polymer blends with different condensed state structure, thermodynamically more facilitation to phase separation （lower Tc） is not necessarily equivalent to faster kinetics （decomposition rate）. The experimental results indicate that the lower Tc of melt-mixed sample is ascribed to smaller concentration fluctuation wavelength （Am） induced by higher entanglement degree, while higher entanglement degree in melt-mixed sample leads to a confined segmental dynamics and consequently a slower kinetics （decomposition rate） dominated by macromolecular diffusion at a comparable quench depth. These results reveal that the chain packing in polymer blends can remarkably influence the liquid-liquid phase separation behavior, which is a significant difference from decomposition of small molecular mixtures.
基金the Key Program of National Natural Science Foundation of China under Grant No.10534030Key Higher Education Program of Hubei Province under Grant No.Z20052201+1 种基金the Natural Science Foundation of Hubei Province under Grant No.2006ABA055the Postgraduate Program of Hubei Normal University under Grant No.2007D20
文摘Considering the dipole-dipole coupling intensity between two atoms and the field in the Fock state, the entanglement dynamics between two atoms that are initially entangled in the system of two two-level atoms coupled to a single mode cavity in the presence of phase decoherence has been investigated. The two-atom entanglement appears with periodicity without considering phase decoherence, however, the phase decoherence causes the decay of entanglement between two atoms, with the increasing of the phase decoherence coefficient, the entanglement will quickly become a constant value, which is affected by the two-atom initial state. Meanwhile the two-atom quantum state will forever stay in the maximal entangled state when the initial state is proper even in the presence of phase decoherence. On the other hand, the Bell violation and the entanglement do not satisfy the monotonous relation, a large Bell violation implies the presence of a large amount of entanglement under certain conditions, while a large Bell violation corresponds to a little amount of entanglement in certain situations. However, the violation of Bell-CHSH inequality can reach the maximal value if two atoms are in the maximal entangled state, or vice versa.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11574092,61775062,61378012,91121023,and 60978009)the National Basic Research Program of China(Grant No.2013CB921804)
文摘We propose a novel scheme for generating the entanglement of two oscillating mirrors in an optomechanical system via a flying atom. In this scheme, a two-level atom, in an arbitrary superposition state, passes through an optomechanical system with two oscillating cavity-mirrors, and then its states are detected. In this way, we can generate the entangled states of the two oscillating mirrors. We derive the analytical expressions of the entangled states and make numerical calculations. We find that the entanglement of the two oscillating mirrors can be controlled by the initial state of the atom, the optomechanical coupling strength, and the coupling strength between the atom and the cavity field. We investigate the dynamics of the system with dissipations and discuss the experimental feasibility.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11305114, 11304226, and 11505126)
文摘In this study, we investigate the phenomenon of distillability sudden death （DSD） for a two-qutrit system coupled to an XY spin chain. In virtue of the negativity and realignment criterion, we show that certain initial-prepared free entangled states may become bound entangled states in a finite time. The possibility of a DSD not only depends on the initial state parameter, but is also determined by the coupling between the two-qutrit system and the spin chain. The effects of other parameters related with the system and the spin chain （e.g., the total number of spins in the spin chain, strengths of the transverse field, and anisotropy parameter） on the time-determined bound entangled state are also investigated in detail. Accordingly, some effective methods of controlling the DSD are proposed.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11105001,10975125,11004001,and 11375168
文摘In this paper,we have investigated the quantum entanglement of quantum states undergoing decoherence from a spin environment which drives a quantum phase transition.From our analysis,we find that the entanglement dynamics depends not only on the coupling strength but also on the external magnetic field and the number of the freedom degrees of the environment.Specially,our results imply that the decay of the entanglement can be enhanced by the quantum phase transition of the environment when the system is coupled to the environment weakly.Additionally,the discussion of the case of the multipartite states with high dimensions is made.
