Quantum entanglement between excitons in two-dimensional materials

TL;DR

This paper investigates quantum entanglement of excitons in two-dimensional materials within a microcavity, revealing conditions for maximally entangled states and how cavity leakage can enhance entanglement.

Contribution

It introduces a model for exciton entanglement in 2D materials, identifying protected maximally entangled states and analyzing the impact of cavity leakage on entanglement dynamics.

Findings

Existence of a maximally entangled eigenstate protected from decay

Cavity leakage can increase average entanglement under certain conditions

Calculated entanglement dynamics in strained graphene monolayers

Abstract

The quantum entanglement between two excitons in two-dimensional materials, embedded in an optical microcavity, was investigated. The energy eigenstates of a Jaynes-Cummings like Hamiltonian for two qubits coupled to a single cavity mode have been calculated. The quantum entanglement between such states was estimated by calculating the concurrence between two qubits in each of these eigenstates. According to the results of our calculations, if the system is allowed to decay only through the emission of cavity photons at low temperatures, there is a maximally entangled eigenstate, protected from decay. We demonstrated that the existence of such a state results in the counter-intuitive conclusion that, for some initial states of the system, the fact that the cavity is leaky can actually lead to an increase in the average concurrence on the timescales of the average photonic lifetime. In addition, we calculated the time evolution of the concurrence between a pair of excitons in a strained graphene monolayer.