Nonreciprocal transport based on cavity Floquet modes in optomechanics

TL;DR

This paper demonstrates a novel method for achieving nonreciprocal transport in a single superconducting cavity system by utilizing Floquet modes, simplifying quantum signal processing and topological lattice design.

Contribution

It introduces a new approach to realize nonreciprocal transport using Floquet modes in a single cavity, reducing system complexity.

Findings

Achieved directional transport using Floquet modes in a superconducting cavity.

Demonstrated cooling of mechanical oscillators close to quantum noise limits.

Identified a new instability specific to nonreciprocal coupling.

Abstract

Directional transport is obtained in various multimode systems by driving multiple, nonreciprocally-interfering interactions between individual bosonic modes. However, systems sustaining the required number of modes become physically complex. In our microwave-optomechanical experiment, we show how to configure nonreciprocal transport between frequency components of a single superconducting cavity coupled to two drumhead oscillators. The frequency components are promoted to Floquet modes and generate the missing dimension to realize an isolator and a directional amplifier. A second cavity left free by this arrangement is used to cool the mechanical oscillators and bring the transduction noise close to the quantum limit. We furthermore uncover a new type of instability specific to nonreciprocal coupling. Our approach is generic and can greatly simplify quantum signal processing and the design of topological lattices from low-dimensional systems.