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Quantum Decoherence of a Spin System Strongly Coupled to a Quantum Environment (研究会報告第8回「非平衡系の統計物理」シンポジウム)

智香子内山

物性研究Feb 20, 20010 citations

Effect of Decoherence Induced by a Spin Environment on Quantum Channel Capacity

Xiao-San Ma, Mu-Tian Cheng, Guang-Xing Zhao +1 more

We investigate the effect of decoherence from a spin environment on the quantum channel capacity. Our results imply that the time evolution of the quantum channel capacity depends on the number of freedom degrees of the environment, the tunneling element, the initial state of the environment, and the system-environment coupling strength. From the analysis, we find that the strong tunneling elements and the weak coupling strength can enhance the quantum channel capacity while the environment with a large number of freedom degrees and the strong coupling strength will shrink it.We investigate the effect of decoherence from a spin environment on the quantum channel capacity. Our results imply that the time evolution of the quantum channel capacity depends on the number of freedom degrees of the environment, the tunneling element, the initial state of the environment, and the system-environment coupling strength. From the analysis, we find that the strong tunneling elements and the weak coupling strength can enhance the quantum channel capacity while the environment with a large number of freedom degrees and the strong coupling strength will shrink it.

Communications in Theoretical PhysicsMar 1, 20121 citation

Quantum capacity of dephasing channels with memory

Antonio D’Arrigo, Giuliano Benenti, G. Falci

We show that the amount of coherent quantum information that can be reliably transmitted down a dephasing channel with memory is maximized by separable input states. In particular, we model the channel as a Markov chain or a multimode environment of oscillators. While in the first model, the maximization is achieved for the maximally mixed input state, in the latter it is convenient to exploit the presence of a decoherence-protected subspace generated by memory effects. We explicitly compute the quantum channel capacity for the first model while numerical simulations suggest a lower bound for the latter. In both cases memory effects enhance the coherent information. We present results valid for arbitrary input size.We show that the amount of coherent quantum information that can be reliably transmitted down a dephasing channel with memory is maximized by separable input states. In particular, we model the channel as a Markov chain or a multimode environment of oscillators. While in the first model, the maximization is achieved for the maximally mixed input state, in the latter it is convenient to exploit the presence of a decoherence-protected subspace generated by memory effects. We explicitly compute the quantum channel capacity for the first model while numerical simulations suggest a lower bound for the latter. In both cases memory effects enhance the coherent information. We present results valid for arbitrary input size.

arXiv:quant-ph/0703014New Journal of PhysicsSep 7, 200795 citations

Effect of decoherence from a spin environment on the entanglement dynamics of two-qutrit states

Xiao-San Ma, Ming-Fan Ren, Guang-Xing Zhao +1 more

Science China Physics Mechanics and AstronomyAug 6, 201110 citations

Intrinsic decoherence dynamics and dense coding in dipolar spin system

Youssef Khedif, R. Muthuganesan

Abstract The quantum decoherence is an ineluctable process when a quantum system interacts with its surrounding environment. Milburn’s dynamical master equation, as a modified shape of the Schrödinger equation, is typically used to study the effects decoherence even without intervention of environment. We studied the temporal evolution of non-local correlations in a dipolar-coupled spin system under the influence of intrinsic decoherence. Primarily, the generation in correlations of Einstein–Podolsky–Rosen steering, measurement-induced non-locality (MIN) and entanglement in an uncorrelated initial system state were studied. Also, the effect of the intrinsic decoherence on the quality of the dense coding capacity dynamics for the dipolar-coupled spin system was examined. Our results highlight that the initial system’s role in defining the quantum correlations’ robustness, and we also brought out the impacts of system’s parameters on the non-local correlations and the efficiency of dense coding processAbstract The quantum decoherence is an ineluctable process when a quantum system interacts with its surrounding environment. Milburn’s dynamical master equation, as a modified shape of the Schrödinger equation, is typically used to study the effects decoherence even without intervention of environment. We studied the temporal evolution of non-local correlations in a dipolar-coupled spin system under the influence of intrinsic decoherence. Primarily, the generation in correlations of Einstein–Podolsky–Rosen steering, measurement-induced non-locality (MIN) and entanglement in an uncorrelated initial system state were studied. Also, the effect of the intrinsic decoherence on the quality of the dense coding capacity dynamics for the dipolar-coupled spin system was examined. Our results highlight that the initial system’s role in defining the quantum correlations’ robustness, and we also brought out the impacts of system’s parameters on the non-local correlations and the efficiency of dense coding process

Dec 6, 20220 citations

Decoherence Effect on Quantum Correlation and Entanglement in a Two-qubit Spin Chain

Mohammad Reza Pourkarimi, Majid Rahnama, Hossein Rooholamini

arXiv:1211.5907International Journal of Theoretical PhysicsAug 21, 201425 citations

Effect of Decoherence Induced by a Spin Environment on Quantum Channel Capacity

Abstract

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Effect of Decoherence Induced by a Spin Environment on Quantum Channel Capacity

Abstract

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