Quantum systems with designer interactions using Floquet physics

Invited Talk

Atoms and photons both provide fantastic experimental platforms for exploring new realms of quantum many-body physics. However, the scope of these platforms is often limited by the available interactions; typical ultracold atoms provide only elastic contact interactions, while photons ordinarily do not interact with each other at all. Our approach to overcoming this limitation is Floquet physics, in which periodic modulation imbues a system with exciting new properties. In this talk, I will discuss three experiments which use modulation to design new interaction processes that enable us to study intriguing many-body physics. First, in the simplest example, we create controlled inelastic collisions between ultracold atoms in a quantum degenerate gas. Even here, the designed interactions induce a rich new dynamical process in which Bose-Einstein condensates explode in a matter-wave fireworks pattern. Second, we make ultracold atoms generate synthetic gauge fields for each other, which can be used to make them act as anyons in a one-dimensional chain. Finally, I will discuss experiments that reverse this paradigm and use Rydberg atoms to generate strong interactions between photons in an optical cavity. By modulating the atoms, we split a single atomic transition into many bands at prescribed energies, enabling us to match the atomic spectrum with the mode spectrum of the cavity. We use this capability to make photons blockade each other throughout multiple transverse modes of an optical cavity for the first time. This Floquet approach paves a new road to generating strongly correlated materials out of light, including crystals and topologically ordered Laughlin states.

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