Quantum entanglement of multiple excitons in strained graphene

TL;DR

This study explores how coherent photon sources induce and sustain entanglement among multiple excitons in strained graphene, revealing dependencies on strain, photon pumping rate, and system size.

Contribution

It demonstrates the creation and control of multi-exciton entanglement in strained graphene within an optical microcavity, highlighting the effects of strain and pumping parameters.

Findings

Entanglement persists only when photon pumping rate is below cavity decay rate.

Strain increases the degree of exciton entanglement.

Maximum entanglement occurs at a specific number of excitons depending on system parameters.

Abstract

We studied the effects arising from a coherent source of photons on the entanglement between excitons in a strained graphene monolayer. The graphene layer was considered to be embedded in an imperfect optical microcavity. In our investigation, we have studied the entanglement dynamics of systems consisting of up to five excitons, which are treated as atomic-like qubits. Entangled states of multiple qubits are useful in quantum error correction codes. We have monitored the time evolution of the concurrence, three-$\pi$, mutual information, and especially the negativity. We have demonstrated that coherent pumping can create lasting entanglement between the excitons. However, the entanglement only persists when the rate at which photons are pumped is smaller than the decay rate of the cavity. Our results show that the degree in entanglement between the excitons is increased with the intensity of the strain-induced pseudomagnetic field in the graphene sheet. Additionally, we have shown that a maximum amount of entanglement occurs at a finite number of excitons in the system which depends on the parameters describing the structure.