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Entanglement between a qubit and the environment in the spin-boson model

T. A. Costi·Ross H. McKenzie
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Abstract

The quantitative description of the quantum entanglement between a qubit and its environment is considered. Specifically, for the ground state of the spin-boson model, the entropy of entanglement of the spin is calculated as a function of $α$, the strength of the ohmic coupling to the environment, and $ε$, the level asymmetry. This is done by a numerical renormalization group treatment of the related anisotropic Kondo model. For $ε=0$, the entanglement increases monotonically with $α$, until it becomes maximal for $α\lim 1^-$. For fixed $ε>0$, the entanglement is a maximum as a function of $α$ for a value, $α= α_M < 1$.

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T. A. Costi, Ross H. McKenzie. 2003-09-08. Entanglement between a qubit and the environment in the spin-boson model. https://doi.org/10.1103/physreva.68.034301

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