Rotating Bose-Einstein condensates confined in an anharmonic potential

Abstract

We consider bosonic atoms that rotate in an anharmonic trapping potential. Using numerical diagonalization of the Hamiltonian, we get evidence for various phases of the gas for different values of the coupling between the atoms and of the rotational frequency of the trap. These include vortex excitation of single and multiple quantization, the phase of center-of-mass excitation, and the unstable phase.

Semiclassical Hartree-Fock theory of a rotating Bose-Einstein condensation

“…The gas is set in rotation using an anisotropic quadratic potential V in the xy plane, rotating at angular frequency Ω around the z axis. In the rotating frame, this stirring potential reads [18,19],…”

Hartree-Fock Approach for Rotating Bose-Einstein Condensation in One-dimensional Deep Optical Lattice

“…Finally the total number of particles is given by (20) Similarly, using the same procedure, one can also obtain results for the total energy [9], (21) and the local grand potential, (…”

Quantized Vortices in Atomic Bose-Einstein Condensates

“…The hyperfine state is denoted by |F, m F with m F = −F, −F + 1, · · · , F − 1, F . The simultaneous trapping of atoms with different hyperfine sublevels makes it possible to create multicomponent (often called "spinor") BECs with internal degrees of freedom (Ho 1998, Ohmi 1998, characterized by multiple order parameters (Hall 1998, Barrett 2001, Schmaljohann 2004, Chang 2004, Kuwamoto 2004). An external field can couple the internal sublevels of the atom and cause coherent transition of the population.…”

“…This restriction can be avoided by introducing an additional quartic potential, so that the combined trapping potential in the xy plane becomes V ex (r) = (1/2)mω 2 ⊥ (r 2 + λr 4 /a 2 ho ), where the dimensionless parameter λ characterizes the relative strength of the quartic potential. The properties of a rotating condensate in an anharmonic potential have recently attracted a lot of theoretical attention (Fetter 2001b, Lundh 2002, Fischer 2003, Kasamatsu 2002a, Kavoulakis 2003, Aftalion 2004, Jackson 2004a,b, Fetter 2005, Danaila 2005, Kim 2005, Bargi 2006, Fu 2006. The vortex phases in an anharmonic trap are quite different from those in a harmonic trap, since it is possible to rotate the system arbitrarily fast.…”