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arXiv 1104.5306cond-mat.stat-mechquant-ph
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量子相变中耗散的模型研究

Model study of dissipation in quantum phase transitions

Subhasis Sinha, Sushanta Dattagupta

摘要:

本文考虑一个无限程横场伊辛模型与玻色浴耦合的原型系统。通过对玻色度积分,得到了自旋系统的有效各向异性海森堡模型。后者的相图计算作为耦合到热浴和横向磁场的函数。在低温下的集体激发进行评估内的自旋波分析,表现出消失的能隙在量子临界点。我们还考虑了另一个限制,系统减少到一个广义的自旋玻色子模型的两个相互作用的自旋。通过增加与热浴的耦合强度,双自旋波函数从纠缠态变为沿横向场排列的双自旋的因式分解态。我们还讨论了该模型在不同物理系统中的可能实现和应用。

英文摘要:

We consider a prototypical system of an infinite range transverse field Ising model coupled to a bosonic bath. By integrating out the bosonic degrees, an effective anisotropic Heisenberg model is obtained for the spin system. The phase diagram of the latter is calculated as a function of coupling to the heat bath and the transverse magnetic field. Collective excitations at low temeratures are assessed within a spin-wave like analysis that exhibits a vanishing energy gap at the quantum critical point. We also consider another limit where the system reduces to a generalized spin-boson model of two interacting spins. By increasing the coupling strength with the heat bath, the two-spin wavefunction changes from an entangled state to a factorized state of two spins which are aligned along the transverse field. We also discuss the possible realization and application of the model to different physical systems.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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