Arko Roy

By using stochastic Gross-Pitaevskii formalism and Hartee-Fock theory, we show that thermal fluctuations in a 2D mixture of two Bose gases are much more important than in 3D: not only they inhibit true Bose-Einstein condensation, as already well known, but they also smoothen all sharp features in the miscible to immiscible phase transition at finite temperature, causing mean-field theories to be inadequate.

We propose the implementation of a quantum heat pump with ultracold atoms. It is based on two periodically driven coherently coupled quantum dots using ultracold atoms. We characterize the device using Floquet theory and compare simple analytical estimates to numerical simulations based on the Floquet-Born-Markov formalism. In particular, we show that driving-induced heating is directly linked to the micromotion of the Floquet states of the system.

We predict the emergence of the third Goldstone mode in binary condensates at phase-separation, which persists to higher inter-species interaction for density profiles where one component is surrounded on both sides by the other component. We use Hartree-Fock-Bogoliubov theory with Popov approximation to examine the mode evolution at finite temperature and demonstrate the existence of mode bifurcation near the critical temperature.

The interaction of a vortex dipole with a Gaussian barrier in BEC enhnaces the acoustic radiation from the vortex dipole. Due to the acoustic radiation, the vortex dipole dissipates energy and spirals towards the edge of the condensate. As a result, we observe an increase in the vortex-antivortex annihilation events.