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arXiv 2402.09510cond-mat.str-elcond-mat.stat-mechhep-thmath-phmath.MP
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非厄米特Kondo模型中的耗散驱动相变

Dissipation driven phase transition in the non-Hermitian Kondo model

Rutgers University(罗格斯大学);University of Maryland, College Park(马里兰大学帕克分校);Laboratory for Physical Sciences(物理科学实验室);Sorbonne Université(索邦大学);CNRS(法国国家科学研究中心)

Pradip Kattel, Abay Zhakenov, Parameshwar R. Pasnoori, Patrick Azaria, Natan Andrei

AI总结:

研究非厄米特Kondo模型中耗散驱动的相变,通过Bethe ansatz发现新的YSR相,并探讨损耗强度参数α对Kondo效应和杂质屏蔽的影响。

摘要:

非厄米特哈密顿量捕捉开放量子系统多个方面,如能量耗散和非幺正演化。例如,在光学晶格中,两个轨道移动原子在基态之间的非弹性散射与处于特定站点的亚稳态原子之间的散射导致双体损失。文献[1]表明,这种效应可通过非厄米特Kondo模型捕捉,该模型根据损耗强度表现出两种相:当损耗较弱时,系统处于Kondo相;当损耗更强时,系统处于未屏蔽相,Kondo效应消失,杂质未被屏蔽。通过Bethe ansatz重新审视该模型发现,除了上述两种相外,系统还表现出新的$\widetilde{YSR}$相,该相位于Kondo相和未屏蔽相之间。该模型由两个重整化群不变量表征,即广义Kondo温度$T_K$和参数$α$,后者衡量损耗强度。Kondo相发生在损耗较弱时,对应$0<α<π/2$。当$α$接近$π/2$时,Kondo云缩小,形成单粒子束缚态,该态在$π/2<α<π$之间屏蔽杂质。当$α$增大时,杂质在基态未被屏蔽,但在$π<α<3π/2$时可通过局域束缚态屏蔽。当$α>3π/2$时,进入未屏蔽相,杂质无法被屏蔽。我们认为,除了能量外,系统在$α=π/2$处表现出不同的时间尺度,导致由系统耗散驱动的相变。

英文摘要:

Non-Hermitian Hamiltonians capture several aspects of open quantum systems, such as dissipation of energy and non-unitary evolution. An example is an optical lattice where the inelastic scattering between the two orbital mobile atoms in their ground state and the atom in a metastable excited state trapped at a particular site and acting as an impurity, results in the two body losses. It was shown in \cite{nakagawa2018non} that this effect is captured by the non-Hermitian Kondo model. which was shown to exhibit two phases depending on the strength of losses. When the losses are weak, the system exhibits the Kondo phase and when the losses are stronger, the system was shown to exhibit the unscreened phase where the Kondo effect ceases to exist, and the impurity is left unscreened. We re-examined this model using the Bethe Ansatz and found that in addition to the above two phases, the system exhibits a novel $\widetilde{YSR}$ phase which is present between the Kondo and the unscreened phases. The model is characterized by two renormalization group invariants, a generalized Kondo temperature $T_K$ and a parameter `$α$' that measures the strength of the loss. The Kondo phase occurs when the losses are weak which corresponds to $0<α<π/2$. As $α$ approaches $π/2$, the Kondo cloud shrinks resulting in the formation of a single particle bound state which screens the impurity in the ground state between $π/2<α<π$. As $α$ increases, the impurity is unscreened in the ground state but can be screened by the localized bound state for $π<α<3π/2$. When $α>3π/2$, one enters the unscreened phase where the impurity cannot be screened. We argue that in addition to the energetics, the system displays different time scales associated with the losses across $α=π/2$, resulting in a phase transition driven by the dissipation in the system.

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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