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arXiv 1302.4891quant-phcond-mat.str-el
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自旋玻色子模型的量子临界点与玻色浴中的红外灾变

Quantum critical point of spin-boson model and infrared catastrophe in bosonic bath

Hang Zheng, Zhiguo Lü

摘要:

提出了一种非高斯的、超越Silbey-Harris基态的、具有较低基态能量的无偏自旋玻色子哈密顿量的解析基态.欧姆和亚欧姆玻色子浴中的红外突变对确定基态的简并度起着重要的作用。我们表明,红外发散与浴中的非绝热模式的位移可能会被删除的耦合$α<α_c$从建议的基态。那么$α_c$是从非简并到简并基态跃迁的量子临界点,我们计算的$α_c$与以前的数值结果一致.

英文摘要:

An analytic ground state is proposed for the unbiased spin-boson Hamiltonian, which is non-Gaussian and beyond the Silbey-Harris ground state with lower ground state energy. The infrared catastrophe in Ohmic and sub-Ohmic bosonic bath plays an important role in determining the degeneracy of the ground state. We show that the infrared divergence associated with the displacement of the nonadiabatic modes in bath may be removed from the proposed ground state for the coupling $α<α_c$. Then $α_c$ is the quantum critical point of a transition from non-degenerate to degenerate ground state and our calculated $α_c$ agrees with previous numerical results.

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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