Quantum optics with giant atoms in a structured photonic bath

TL;DR

This paper develops a comprehensive theoretical framework for quantum optics involving giant atoms coupled to structured photonic baths, enabling the prediction and engineering of decoherence-free Hamiltonians across various lattice structures.

Contribution

It introduces a general formalism for giant atoms in structured baths and provides a novel criterion for designing decoherence-free Hamiltonians in diverse photonic environments.

Findings

Derived Green's functions and bound states for giant atoms

Established a criterion for engineering decoherence-free Hamiltonians

Demonstrated novel decoherence-free Hamiltonians in 2D photonic lattices

Abstract

We present a general framework to tackle quantum optics problems with giant atoms, i.e. quantum emitters each coupled {\it non-locally} to a structured photonic bath (typically a lattice) of any dimension. The theory encompasses the calculation and general properties of Green's functions, atom-photon bound states (BSs), collective master equations and decoherence-free Hamiltonians (DFHs), and is underpinned by a formalism where a giant atom is formally viewed as a normal atom lying at a fictitious location. As a major application, we provide for the first time a general criterion to predict/engineer DFHs of giant atoms, which can be applied both in and out of the photonic continuum and regardless of the structure or dimensionality of the photonic bath. This is used to show novel DFHs in 2D baths such as a square lattice and photonic graphene.