Theory for entanglement of electrons dressed with circularly polarized light in Graphene and three-dimensional topological insulators

TL;DR

This paper develops a theoretical framework to understand how circularly polarized light can induce and control electron entanglement in graphene and topological insulators by modifying their electronic band structure and exchange interactions.

Contribution

The study introduces a novel theory linking light-induced band gaps and electron-photon interactions to entanglement control in 2D materials and topological insulators.

Findings

Circularly polarized light opens a tunable energy gap at the Fermi level.

Doping significantly influences exchange energy and entanglement.

Energy dispersion of dressed states is unique and different from graphene or 2DEG.

Abstract

We have formulated a theory for investigating the conditions which are required to achieve entangled states of electrons on graphene and three-dimensional (3D) topological insulators (TIs). We consider the quantum entanglement of spins by calculating the exchange energy. A gap is opened up at the Fermi level between the valence and conduction bands in the absence of doping when graphene as well as 3D TIs are irradiated with circularly-polarized light. This energy band gap is dependent on the intensity and frequency of the applied electromagnetic field. The electron-photon coupling also gives rise to a unique energy dispersion of the dressed states which is different from either graphene or the conventional two-dimensional electron gas (2DEG). In our calculations, we obtained the dynamical polarization function for imaginary frequencies which is then employed to determine the exchange energy. The polarization function is obtained with the use of both the energy eigenstates and the overlap of pseudo-spin wave functions. We have concluded that while doping has a significant influence on the exchange energy and consequently on the entanglement, the gap of the energy dispersions affects the exchange slightly, which could be used as a good technique to tune and control entanglement for quantum information purposes.