Beyond Spontaneous Emission: Giant Atom Bounded in Continuum

Understand

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.