Crystallization of strongly interacting photons in a nonlinear optical fiber

Understanding strongly correlated quantum systems is a central problem in many areas of physics. The collective behavior of interacting particles gives rise to diverse fundamental phenomena such as confinement in quantum chromodynamics, phase transitions, and electron fractionalization in the quantum Hall regime. While such systems typically involve massive particles, optical photons can also interact with each other in a nonlinear medium. In practice, however, such interactions are often very weak. Here we describe a novel technique that allows the creation of a strongly correlated quantum gas of photons using one-dimensional optical systems with tight field confinement and coherent photon trapping techniques. The confinement enables the generation of large, tunable optical nonlinearities via the interaction of photons with a nearby cold atomic gas. In its extreme, we show that a quantum light field can undergo fermionization in such one-dimensional media, which can be probed via standard photon correlation measurements

Slow, Stored and Stationary Light

Slow light has received growing interest since 1999 when the propagation velocity of light was reduced in an experiment to 17 m/s, i.e. almost 20 million times slower than in vacuum. Two years later light pulses were stopped, or more specifically stored in an atomic medium and subsequently released after some time. This provided the basis for important applications in photon-based quantum information technology. The present chapter explains what slow light is and what it is good for, how to understand the physics of it and how one can practically make light go so slow. To answer these questions, the chapter uses simple pictures, on the one hand, and supplements them with a little bit of details, on the other hand, for those who want to go slightly deeper into the field. The chapter also discusses more recent generalizations of slow light, such as stationary and spinor slow light which are interesting model system and can be used to understand more complex quantum systems