Non-ground-state Bose-Einstein condensates of trapped atoms

Abstract

The possibility of creating a Bose condensate of trapped atoms in a non-ground state is suggested. Such a nonequilibrium Bose condensate can be formed if one, first, obtains the conventional Bose condensate in the ground state and then transfers the condensed atoms to a non-ground state by means of a resonance pumping. The properties of ground and non-ground states are compared and plausible applications of such nonequilibrium condensates are discussed. 03.75.Fi

States without a linear counterpart in Bose-Einstein condensates

“…Of particular interest are the non ground-state stationary solutions of the GPE [2,3] which represent macroscopically excited states of the condensate. Vortices have been recently observed in two- [4] or onecomponent [5] condensates and are also invoked as a superfluidity breaking mechanism [6].…”

Nonlinear coherent modes of trapped Bose-Einstein condensates

“…Earlier, we have considered [4,7] only the transitions from the ground state to an excited collective state. But if one is able to transfer atoms from the ground state to an excited level, then by applying one more alternating field, with a different resonant frequency, it is possible to transfer atoms from one excited level to another higher level.…”

“…The feasibility of creating such nonground-state condensates was advanced in Ref. [4]. The properties of these excited self-consistent states and different ways of their formation have been previously discussed in [4][5][6][7][8][9][10][11][12].…”

“…[4]. To some extent, this is analogous to the problem of periodically modulated nonlinear optical fibers [17], as opposed to the adiabatic perturbations of nonlinear soliton equations [18].…”

“…To some extent, this is analogous to the problem of periodically modulated nonlinear optical fibers [17], as opposed to the adiabatic perturbations of nonlinear soliton equations [18]. Our aim here is to develop a thorough theory of the nonlinear coherent modes, analyzing their features that have not been considered in our previous publications [4,7]. The main new points are as follows:…”