理论物理通讯：英文版

Subsystem Dynamics of an Anisotropic Two-Qubit Heisenberg XYZ Chain Coupled Independently to Their Own Environments

李磊, 邹健, 徐宝明, 邵彬

Published Jan 1, 2016• 0 citations

Abstract

We consider a composite system:an anisotropic two-qubit Heisenberg XY Z chain coupled independently to their own environments.We take one of the qubit as the subsystem and the other qubit as an auxiliary qubit,and then the subsystem we concern can be considered to be coupled to a structured bath(auxiliary qubit + environments).Based on this,we study the non-Markovianity of the subsystem dynamics and show how the subsystem dynamics can be changed by manipulating the intensity of the qubit-qubit couplings or the anisotropy parameter.Moreover,we show how entanglement between the subsystem and the structured bath can be affected by the properties of the structured bath and the magnetic field.

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理论物理通讯：英文版

Subsystem Dynamics of an Anisotropic Two-Qubit Heisenberg XYZ Chain Coupled Independently to Their Own Environments

李磊, 邹健, 徐宝明, 邵彬

Published Jan 1, 2016• 0 citations

OpenAlex

Abstract

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Communications in Theoretical PhysicsJun 1, 20105 citations

We consider the quantum correlations (entanglement and quantum discord) dynamics of two coupled spin qubits with Dzyaloshinsky-Moriya interaction influenced by a locally external magnetic field along

z

-direction and coupled to bath spin-1/2 particles as independent non-Markovian environment. We find that with increasing

D_{z}

and decreasing

J_{z}

, the value of entanglement and quantum discord increase for both antiferromagnetic and ferromagnetic materials. Not that, this growth is more for the ferromagnetic materials. In addition, we perceive that entanglement and quantum discord decrease with increased temperature and increased coupling constants between reduced system and bath. But, strong quantum correlations within the spins of bath reduce decoherence effects. We discuss about type of the constituent material of the central spins that it can speedup the quantum information processing and as a result, we perceive that one can improve and control the quantum information processing with correct selection of the properties of the reduced system (

J

J_{z}

D_{z}

The dynamics of two

1∕2

-spin qubits under the influence of a quantum Heisenberg

XY

-type spin-bath is studied. After the Holstein-Primakoff transformation, numerical polynomial scheme is used to give the time-evolution calculation of the center qubits initially prepared in a product state or a Bell state. Then the concurrence of the two qubits, the

z

-component moment of either of the subsystem spins, and the fidelity of the subsystem are shown; they exhibit sensitive dependence on the anisotropic parameter, the temperature, the coupling strength, and the initial state. It is found that (i) the larger the anisotropic parameter $\ensuremath{\gamma}$, the bigger the probability of maintaining the initial state of the two qubits; (ii) with increasing temperature

T

, the bath plays a stronger destroy effect on the dynamics of the subsystem, so does the interaction

{g}_{0}

between the subsystem and the bath; and (iii) the time evolution of the subsystem is dependent on the initial state. The revival of the concurrence does not always mean the restoration of the state. Further, the dynamical properties of the subsystem should be judged by the combination of concurrence and fidelity.