Dynamics and decay of solitons and solitonic vortices in superfluid Fermi gases.

Ultracold quantum gases consist of a collection of magnetically trapped atoms cooled down to nanokelvin temperatures. At these ultralow temperatures, the laws of quantum mechanics, which are usually confined to the microscopic world of atoms and particles, now become apparent on the scale of the entire macroscopic cloud. This leads to remarkable behavior, such as flow without friction or "superfluidity". Superfluids are characterized by a complex order parameter. Phase defects in this order parameter are known as solitonic excitations, such as solitons and vortices. The former are localized density dips that propagate without changing their shape, with classical counterparts in water canals and optical fibers. The latter are quantized "whirlpools". Here, we will study these solitonic excitations in a Fermi quantum fluid by making use of a finite-temperature effective field theory that we developed specifically for these systems. Solitons in Fermi superfluids are experimentally seen to decay into vortices. We will model this decay and propose ways to stabilize solitons. We will also investigate collisions between solitonic excitations, and their spontaneous appearance when a gas is cooled rapidly. Finally, we will investigate how disorder and mixing of superfluids influence the properties of the solitonic excitations.

Keywords:FERMI GASES

Disciplines:Theoretical and computational chemistry, Other chemical sciences