Acoustic analog of the dynamical Casimir effect in a BEC
Chris Westbrook, LCFIO, Palaiseau
Although we often picture the quantum vacuum as containing virtual quanta whose observable effects are only indirect, it is a remarkable prediction of quantum field theory that the vacuum can generate real particles when boundary conditions are suddenly changed. Thus the dynamical Casimir effect results in the spontaneous generation of photon pairs in an empty cavity whose boundaries are rapidly accelerating. A recent experiment has demonstrated this effect in the microwave regime using superconducting circuits. Acoustic analogs of this effect exist as well, and Bose Einstein condensates are attractive candidates in which to study such analogs because their low temperatures promise to reveal quantum effects. I will – describe our group’s work to develop an acoustic analog to the dynamical Casimir effect by modulating the confinement of a Bose-Einstein – condensate. We are able to observe the generation of correlated pairs of excitations both in the phonon and particle-like regimes in a process which also formally resembles parametric down conversion..