Photonic simulation of giant atom decay

Spontaneous emission of an excited atom in a featureless continuum of electromagnetic modes is a fundamental process in quantum electrodynamics associated with an exponential decay of the quantum emitter to its ground state accompanied by an irreversible emission of a photon. However, such a simple scenario is deeply modified when considering a $^{\prime}$giant$^{\prime}$ atom, i.e an atom whose dimension is larger than the wavelength of the emitted photon. In such an unconventional regime, non-Markovian effects and strong deviations from an exponential decay are observed owing to interference effects arising from non-local light-atom coupling. Here we suggest a photonic simulation of non-Markovian giant atom decay, based on light escape dynamics in an optical waveguide non-locally-coupled to a waveguide lattice. Major effects such as non-exponential decay, enhancement or slowing down of the decay, and formation of atom-field dark states can be emulated in this system