Nonlinear quantum logic with colliding graphene plasmons

TL;DR

This paper theoretically explores how colliding graphene plasmons can be used to implement high-fidelity quantum gates, leveraging their strong nonlinear interactions and tunability at the nanoscale.

Contribution

It introduces a novel approach to quantum logic using colliding graphene plasmons, demonstrating the feasibility of a high-fidelity conditional Pi phase shift (CZ) gate.

Findings

Feasibility of a high-fidelity CZ gate with graphene plasmons.

Performance limited only by single-plasmon lifetime.

Potential for quantum information applications with strongly-interacting polaritons.

Abstract

Graphene has emerged as a promising platform to bring nonlinear quantum optics to the nanoscale, where a large intrinsic optical nonlinearity enables long-lived and actively tunable plasmon polaritons to strongly interact. Here we theoretically study the collision between two counter-propagating plasmons in a graphene nanoribbon, where transversal subwavelength confinement endows propagating plasmons with %large effective masses a flat band dispersion that enhances their interaction. This scenario presents interesting possibilities towards the implementation of multi-mode polaritonic gates that circumvent limitations imposed by the Shapiro no-go theorem for photonic gates in nonlinear optical fibers. As a paradigmatic example we demonstrate the feasibility of a high fidelity conditional Pi phase shift (CZ), where the gate performance is fundamentally limited only by the single-plasmon lifetime. These results open new exciting avenues towards quantum information and many-body applications with strongly-interacting polaritons.