Beyond Spontaneous Emission: Giant Atom Bounded in Continuum

TL;DR

This paper explores a giant atom model coupled to surface acoustic waves, revealing suppressed relaxation and vacuum coupling effects, with implications for quantum acoustic devices.

Contribution

It introduces an exactly solvable model for a giant atom coupled to surface acoustic waves, highlighting non-Markovian effects and potential practical implementations.

Findings

Suppressed relaxation of the giant atom.

Effective vacuum coupling without a cavity.

Potential for quantum acoustic device applications.

Abstract

The quantum coupling of individual superconducting qubits to microwave photons leads to remarkable experimental opportunities. Here we consider the phononic case where the qubit is coupled to an electromagnetic surface acoustic wave antenna that enables supersonic propagation of the qubit oscillations. This can be considered as a giant atom that is many phonon wavelengths long. We study an exactly solvable toy model that captures these effects, and find that this non-Markovian giant atom has a suppressed relaxation, as well as an effective vacuum coupling between a qubit excitation and a localized wave packet of sound, even in the absence of a cavity for the sound waves. Finally, we consider practical implementations of these ideas in current surface acoustic wave devices.