Abstract
Strong coupling between a local quantum system and extended bosonic states has recently become experimentally feasible in a variety of plasmonic, photonic, circuit-QED, and cold-atom contexts. This has opened up a new field dubbed "waveguide QED". I first introduce several of the experimental systems and the basic quantum non-linear optics problems they can address. Then, turning to our own results, I present an exact solution of the quantum transport problem of photons in a waveguide strongly coupled to a two-, three-, or four- level system. We explore the dramatic quantum optics effects in these systems. In particular, multi-photon correlated states emerge in the scattering of two or more photons, which then have a large impact on the transport of coherent-state wave-packets such as causing photon blockade. In addition, we study a two qubit waveguide QED system, obtaining the first results beyond the Markovian approximation. Two surprising results emerged: quantum interference effects in the correlations of the photons and a high degree of long-distance entanglement between the two qubits. Such nonlinear phenomena in open systems can play a critical role in the manipulation of individual, mobile quanta, which is a key goal of quantum information processing and communication.
Coffee and tea will be served 20 minutes prior to the seminar.