Frictionless flow in a binary polariton superfluid.

Optical superfluid phase transitions and trapping of polariton condensates.

Semiconductor microcavities are used to support freely flowing polariton quantum liquids allowing the direct observation and optical manipulation of macroscopic quantum states. Incoherent optical excitation at a point produces radially expanding condensate clouds within the planar geometry. By using arbitrary configurations of multiple pump spots, we discover a geometrically controlled phase tr...

From single particle to superfluid excitations in a dissipative polariton gas.

Using an angle-resolved heterodyne four-wave-mixing technique, we probe the low momentum excitation spectrum of a coherent polariton gas. The experimental results are well captured by the Bogoliubov transformation which describes the transition from single particle excitations of a normal fluid to soundlike excitations of a superfluid. In a dense coherent polariton gas, we find all the characte...

Polariton condensates put in motion.

We present several examples of the interesting phenomenology shown by a moving polariton condensate in semiconductor microcavities. The superfluid behavior is probed by colliding the polariton condensate against physical obstacles in the form of natural defects of the sample, demonstrating a clear suppression of scattering when the speed of the flow lies below the critical velocity. At higher v...

Hydrodynamic nucleation of vortices and solitons in a resonantly excited polariton superfluid

The Discovery of Superfluidity

T of the greatest physics discoveries in the first half of the 20th century were superconductivity and superfluidity. Superconductivity involves the frictionless conduction of electricity in wires, and superfluidity the frictionless flow of superfluid liquid helium through channels. Both discoveries led to the arcane phenomenon of macroscopic quantization: the manifestation of the laws of quant...