局域化耗散量子输运
Locality Bound for Dissipative Quantum Transport.
机构信息
Department of Physics, Stanford University, Stanford, California 94305, USA.
出版信息
Phys Rev Lett. 2018 Oct 26;121(17):170601. doi: 10.1103/PhysRevLett.121.170601.
We prove an upper bound on the diffusivity of a dissipative, local, and translation invariant quantum Markovian spin system: D≤D_{0}+(αv_{LR}τ+βξ)v_{C}. Here v_{LR} is the Lieb-Robinson velocity, v_{C} is a velocity defined by the current operator, τ is the decoherence time, ξ is the range of interactions, D_{0} is a decoherence-induced microscopic diffusivity, and α and β are precisely defined dimensionless coefficients. The bound constrains quantum transport by quantities that can either be obtained from the microscopic interactions (D_{0}, v_{LR}, v_{C}, ξ) or else determined from independent local nontransport measurements (τ, α, β). We illustrate the general result with the case of a spin-half XXZ chain with on-site dephasing. Our result generalizes the Lieb-Robinson bound to constrain the sub-ballistic diffusion of conserved densities in a dissipative setting.
我们证明了耗散的、局部的、平移不变的量子马尔可夫自旋系统的扩散系数的一个上界：D≤D_{0}+(αv_{LR}τ+βξ)v_{C}。这里 v_{LR} 是 Lieb-Robinson 速度，v_{C} 是由电流算子定义的速度，τ 是退相干时间，ξ 是相互作用的范围，D_{0} 是由退相干引起的微观扩散系数，α 和 β 是精确定义的无量纲系数。这个边界通过可以从微观相互作用（D_{0}、v_{LR}、v_{C}、ξ）中获得的量或者从独立的局部非传输测量（τ、α、β）来限制量子输运。我们用一个带有局域去相位的自旋-1/2 XXZ 链的例子来说明这个一般结果。我们的结果将 Lieb-Robinson 边界推广到耗散环境中约束守恒密度的亚弹道扩散。
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