Strong repulsive and attractive interactions in correlated dipolar quantum fluids

Quantum fluids of matter with long range, anisotropic interactions display rich emergent collective phenomena. A prominent example is the dipole-dipole interaction, which has recently been addressed by a growing community, both from atomic physics as well as from condensed matter physics, with the latter being focused on dipolar quantum fluids of two-dimensional excitons, and very recently, on the introduction of interacting dipolar polaritons. These strongly interacting dipolar exciton and polariton systems offer opportunities to explore new collective phenomena which are currently inaccessible with atomic dipolar gases, and to demonstrate new types of quantum devices on the level of two-particle interaction.

In this talk I will present several recent results in systems of dipolar excitons and polaritons. These include strong experimental evidence for the dynamical formation of a robust dark quantum liquid phase of dipolar excitons in a bilayer system. This observation is corroborated by a surprising theory predicting a remarkable stabilization of a dense dark-spin exciton Bose-Einstein condensate, driven by particle correlations due to the strong dipolar interactions.  Also, I will report on the first observation of a formation of an attractive polaron-like many-body correlated state of vertically coupled dipolar exciton fluids. Finally, I will introduce recent experiments showing formation of flying electrically polarized dipolar-polaritons (dipolaritons) in optical waveguides, resulting in a very large, electrically tunable enhancement of the polariton-polariton interactions, a result promising for future implementations of a dipolar polariton blockade.