Long range entanglement in quantum dot systems under the Fermi-Hubbard approach

TL;DR

This paper investigates how Coulomb interactions influence pairwise entanglement in quantum dot systems modeled by the Fermi-Hubbard approach, revealing extended entanglement ranges and detailed pair descriptions.

Contribution

It introduces a detailed analysis of Coulomb effects on entanglement range and provides a rigorous description of entangled pairs in quantum dot systems.

Findings

Entanglement range extends to third neighbors for L=4

Coulomb interaction enables entanglement extension for L>4

Pairs are described by local half-filled states with N=2 and S=0

Abstract

In the present paper we are interested in analyzing the pairwise entanglement in quantum dots, as ququart systems, naturally described by the Fermi-Hubbard model. Using the lower bound of concurrence we show the effect of the Coulomb interaction on the pairwise entanglement and creating entanglement within the pairs. Specifically, it is shown that the range of entanglement can be extended to the third neighboring site for a system size of $L=4$, while for $L>4$ the range could be created and extended to the third neighboring site by means of the Coulomb interaction. A rigorous description of the pairs is given in terms of a local half filled state associated to each pair with an electron number $N=2$ and a spin $S=0$. A thorough study of this state provides a proper explanation related to the pairwise entanglement, namely its amount and its behavior under the effect of the Coulomb interaction as well as the system's size.