A graphene edge-mediated quantum gate

TL;DR

This paper introduces a graphene-based quantum gate that uses edge states to control magnetic interactions, enabling electrostatic tuning of entanglement for potential quantum computing applications.

Contribution

It presents a novel graphene edge-mediated quantum gate architecture with tunable exchange interactions controlled by carrier density.

Findings

Exchange interaction can be switched from ferro to antiferromagnetic.

Device operation regimes depend on size and coupling parameters.

Simplified models effectively describe many-body mechanisms.

Abstract

We propose a quantum gate architecture that allows for the systematic control of the effective exchange interactions between magnetic impurities embedded in nano-scale graphene flakes connected by a gated bridge. The entanglement between the magnetic moment and the edge states of the fragments is used to electrostatically tune the exchange interaction from ferro to antiferromagnetic by merely changing the bridge's carrier density. By characterizing the effects of size and coupling parameters, we explore different operation regimes of this device by means of exact calculations with the density matrix renormalization group (DMRG). We analyze the results utilizing a simplified model that accounts for the main many-body mechanisms. Finally, we discuss how to use arrays of these devices to build quantum simulators for quantum many-body Hamiltonians.