Magnon cat states in a cavity-magnon-qubit system via two-magnon driving and dissipation

TL;DR

This paper introduces a method to generate magnonic cat states in a cavity-magnon-qubit system through two-magnon driving and dissipation, enabling the creation of non-classical states useful for quantum sensing.

Contribution

The authors propose a novel dissipative protocol for generating magnonic cat and squeezed states using two-magnon interactions and qubit dissipation in a hybrid system.

Findings

Magnon cat states can be generated via two-magnon driving and dissipation.

Magnon squeezed states may appear during short-time evolution.

The method enables creation of macroscopic quantum states for quantum sensing.

Abstract

We propose an efficient method for dissipative generation of magnonic cat states in a cavity-magnon-qubit hybrid system by exploiting a two-magnon driving and dissipation mechanism. When both the magnon and qubit are driven, a coherent nonlinear two-magnon interaction is induced, wherein the qubit and the magnon mode exchange energy through magnon pairs. The dissipation of the qubit is exploited to steer the magnon mode into a quantum superposition of distinct coherent states, where the magnon mode evolves into either an even or odd cat state, depending on the parity of the magnon initial state. For the case where the magnon initial state is a superposition state, e.g., of $\ket{0}$ and $\ket{1}$, the magnon mode can evolve into a weighted mixture of the even and odd cat states. We also find that magnon squeezed states may emerge during the short-time evolution, showcasing the capability of our mechanism in preparing diverse magnon non-classical states. Magnonic cat and squeezed states are macroscopic quantum states and find applications in macroscopic quantum studies and quantum sensing, e.g., in the dark matter search using ferromagnetic axion haloscopes.