Macroscopic quantum tunneling of two-component Bose-Einstein condensates

Abstract

We show theoretically the existence of a metastable state and the possibility of decay to the ground state through macroscopic quantum tunneling in two-component Bose-Einstein condensates with repulsive interactions. Numerical analysis of the coupled Gross-Pitaevskii equations clarifies the metastable states whose configuration preserves or breaks the symmetry of the trapping potential, depending on the interspecies interaction and the particle number. We calculate the tunneling decay rate of the metastable state by using the collective coordinate method under the WKB approximation. Then the height of the energy barrier is estimated by the saddle point solution. It is found that macroscopic quantum tunneling is observable in a wide range of particle numbers. Macroscopic quantum coherence between two distinct states is discussed; this might give an additional coherent property of two-component Bose condensed systems. Thermal effects on the decay rate are estimated.

Segregation and symmetry breaking of strongly coupled two-component Bose–Einstein condensates in a harmonic trap

“…We expect the derivatives of u ∞ and v ∞ to be not continuous trough the nodal line {u ∞ = v ∞ = 0}, and the system (1.7) to be solved only in the interior of the supports of u ∞ and v ∞ . In [22] and [25], we find simulations supporting this idea. In addition, in the case when g 1 = g 2 , we conjecture that the difference of the two components is a smooth function.…”

Classification of the ground states and topological defects in a rotating two-component Bose-Einstein condensate

“…Examples of the rotating droplet ground states can be seen in Fig. 4(a), and further examples can be found in [22,[36][37][38][39].…”

Domain wall suppression in trapped mixtures of Bose-Einstein condensates

“…In Table I we compare our results with those of Ref. [11]. It is manifest that, while for the symmetrypreserving (double-wall) state the two results are identical up to the fourth significant digit, our regularization method enables us to attain a stricter upper bound for the ground-state energy of the symmetry-breaking (single-wall) configuration.…”