Entanglement of an impurity and conduction spins in the Kondo model

Impurity entanglement entropy in Kondo systems from conformal field theory

The entanglement entropy in Kondo impurity systems is studied analytically using conformal field theory. From the impurity contribution to the scaling corrections of the entanglement entropy we extract information about the screening cloud profile for general non-Fermi-liquid fixed points. By also considering the finite-temperature corrections to scaling of the von Neumann entropy we point out a direct connection between the large-distance screening cloud profile and thermodynamic observables such as the specific heat.

Kondo nanomechanical dissipation in the driven Anderson impurity model

The cyclic sudden switching of a magnetic impurity from Kondo to a non-Kondo state and back was recently shown to involve an important dissipation of the order of several $k_BT_K$ per cycle. The possibility to reveal this and other electronic processes through nanomechanical dissipation by e.g., ultrasensitive Atomic Force Microscope (AFM) tools currently represents an unusual and interesting form of spectroscopy. Here we explore the dependence on the switching time of the expected dissipation, a quantity whose magnitude is physically expected to drop from maximum to zero between sudden and sl…

Quantum correlations in nanostructured two-impurity Kondo systems

We study the ground-state entanglement properties of nanostructured Kondo systems consisting of a pair of impurity spins coupled to a background of confined electrons. The competition between the RKKY-like coupling and the Kondo effect determines the development of quantum correlations between the different parts of the system. A key element is the electronic filling due to confinement. An even electronic filling leads to results similar to those found previously for extended systems, where the properties of the reduced impurity-spin subsystem are uniquely determined by the spin correlation fu…

Impurity Entanglement Entropy and the Kondo Screening Cloud

The screening of an impurity spin by conduction electrons is associated with the formation of a large Kondo screening cloud, of size xi_K. We study the quantum entanglement between a region of size r surrounding the impurity and the rest of the sample, (of total size R) using Density Matrix Renormalization Group and analytic methods. The corresponding "impurity entanglement entropy", S_{imp}, is shown to be a universal scaling function of r/xi_K and r/R. We calculate this universal function using Fermi liquid theory in the regime xi_K << r.

含两体损耗的安德森杂质模型中的耗散近藤物理

Dissipative Kondo physics in the Anderson Impurity Model with two-body losses

该研究针对含两体损耗的耗散安德森杂质模型，通过自洽NCA方法及数值模拟验证，揭示两体耗散下近藤物理的稳健特征及保护机制，并通过耗散Schrieffer-Wolff变换给出理论解释。

Kondo QED：与光超强耦合的双杂质 Anderson 模型中的 Kondo 效应与光子俘获

Kondo QED: The Kondo effect and photon trapping in a two-impurity Anderson model ultra-strongly coupled to light

本文提出结合Kondo效应与光物质超强耦合的“Kondo QED”系统，利用分层运动方程方法发现超强耦合会抑制Kondo共振并引发光子积累效应，为同时控制这两种效应奠定了基础。

利用碱土金属原子阵列工程化近藤杂质问题

Engineering the Kondo impurity problem with alkaline-earth atom arrays

本文提出用碱土金属原子阵列在光晶格与光镊组合中模拟近藤杂质问题，识别出抑制近藤效应的自旋-电荷竞争项，并通过局域调节化学势恢复近藤效应，为非常规区间近藤物理研究提供新途径。

幺正性之外的单调杂质熵：$\mathscr{PT}-$对称量子杂质模型

Monotonic and non-Nonmonotonic Impurity Entropy flows in a $\mathscr{PT}$-Symmetric Kondo Model

研究非厄米$\mathscr{PT}$对称量子杂质模型中Kondo屏蔽与杂质熵，发现即使边界相互作用非幺正，杂质熵仍从$\ln 4$单调降至0。

PT对称多通道近藤系统中单调杂质熵流的崩溃

Breakdown of Monotonic Impurity Entropy Flow in $\mathscr{PT}$-Symmetric Multichannel Kondo Systems

该研究针对PT对称非厄米多通道近藤模型，发现零模与局域矩相的杂质熵非单调，打破了RG不可逆性的单调熵流规律。

The excitation operator approach to non-Markovian dynamics of quantum impurity models in the Kondo regime

We present a numerical method for studying the real time dynamics of a small interacting quantum system coupled to an infinite fermionic reservoir. By building an orthonormal basis in the operator space, we turn the Heisenberg equation of motion into a system of linear differential equations, which is then solved iteratively by constructing excitation operators. The application of our method depends on a layer structure in the operator space, which help us to turn an infinite linear system into a series of small systems. We apply the method to investigate the decoherence dynamics of quantum im…

超导存在下的近藤过屏蔽

Kondo overscreening in the presence of superconductivity

本文研究超导与过屏蔽近藤效应竞争的自旋-1/2量子杂质模型，揭示强耦合下稳定的过屏蔽近藤相、YSR型中间能隙态以及近藤相与YSR相之间的新相，并与其他竞争机制模型的相图进行类比。