Entanglement switching via the Kondo effect in triple quantum dots

TL;DR

This paper explores how the Kondo effect in a triple quantum dot system can induce switching between entangled and unentangled states, revealing a quantum phase transition influenced by charge fluctuations and modeled by an exactly solvable spin system.

Contribution

It demonstrates the role of the Kondo effect in entanglement switching in a triple quantum dot, including a quantitative analysis of the phase transition and a phase diagram explanation.

Findings

Kondo singlets induce entanglement switching.

Quantum phase transition between entangled and unentangled states.

Phase diagram explained by an exactly solvable spin model.

Abstract

We consider a triple quantum dot system in a triangular geometry with one of the dots connected to metallic leads. Using Wilson's numerical renormalization group method, we investigate quantum entanglement and its relation to the thermodynamic and transport properties, in the regime where each of the dots is singly occupied on average, but with non-negligible charge fluctuations. It is shown that even in the regime of significant charge fluctuations the formation of the Kondo singlets induces switching between separable and perfectly entangled states. The quantum phase transition between unentangled and entangled states is analyzed quantitatively and the corresponding phase diagram is explained by exactly solvable spin model.