Tightly packed ordered arrays of atoms (or, more generally, quantum emitters) exhibit remarkable collective optical properties, as dissipation in the form of photon emission is correlated. In this talk, I will discuss the single-, few- and many-body out-of-equilibrium physics of 1D arrays, and their potential to realize versatile light-matter interfaces. For small enough inter-atomic distances, atomic chains feature dark states that allow for dissipationless transport of photons, behaving as waveguides for single-photon states. Atomic waveguides can be used to mediate interactions between impurity qubits coupled to the array, and allow for the realization of multiple paradigms in waveguide QED, from bandgap physics to chiral quantum optics . Due to the two-level nature of the atoms, atomic waveguides are a perfect playground to realize strong photon-photon interactions. At the many-body level, I will address the open question of how the geometry of the array impacts the process of "Dicke superradiance", where fully inverted atoms synchronize as they de-excite, emitting light in a burst (in contrast to the exponential decay expected from independent emitters). While most literature attributes the quenching of superradiance to Hamiltonian dipole-dipole interactions, the actual culprits are dissipative processes in the form of photon emission into different optical modes. I will provide an understanding of the physics in terms of collective jump operators and demonstrate that superradiance survives at small inter-atomic distances . I will finish my talk by discussing the implications of correlated photon emission for quantum information processing and metrology.
 S. J. Masson, A. Asenjo-Garcia, Atomic-waveguide Quantum Electrodynamics, arXiv: 1912.06234 (2019)
 S. J. Masson, I. Ferrier-Barbut, L. A. Orozco, A. Browaeys, A. Asenjo-Garcia, Many-body signatures of collective decay in atomic chains, arXiv: 2008.08139 (2020)
This seminar is sponsored by the department of Applied Physics and the Ginzton Laboratory.