Magnonic Hong-Ou-Mandel Effect

TL;DR

This paper simulates the propagation of magnons in a yttrium-iron garnet film and demonstrates a controllable semi-transparent magnon mirror capable of producing a Hong-Ou-Mandel effect with single magnons.

Contribution

It introduces an original formalism for simulating magnon propagation and shows how an electrically controlled barrier can act as a semi-transparent mirror for magnons.

Findings

A potential barrier can be tuned to 50% transparency for magnons.

A strong Hong-Ou-Mandel effect is predicted for single magnons.

The setup enables two-magnon quantum interference analogous to photon experiments.

Abstract

We carried out numerical simulations of propagation of spin waves (magnons in quantum language) in a yttrium-iron garnet film. The numerical model is based on an original formalism. We demonstrated that a potential barrier for magnons, created by an Oersted field of a dc current flowing through a wire sitting on top of the film, is able to act as an electrically controlled partly transparent mirror for the magnons. We found that the mirror transparency can be set to 50% by properly adjusting the current strength, thus creating a semi-transparent mirror. A strong Hong-Ou-Mandel Effect for single magnons is expected in this configuration. The effect must be seen as two single magnons, launched simultaneously into the film from two transducers located from the opposite sides of the mirror, creating a two-microwave-photon state at the output port of one of the transducers. The probability of seeing those two-photon states at the output port of either transducer must be the same for both transducers.