arXiv:0911.2355 · Physical Review A

Mixtures of Bose gases confined in concentrically coupled annular traps

Francesc Malet, G. M. Kavoulakis, S. M. Reimann

Published Jan 28, 2010• 24 citations

Abstract

A two-component Bose-Einstein condensate confined in an axially symmetric potential with two local minima, resembling two concentric annular traps, is investigated. The system shows a number of phase transitions that result from the competition between phase coexistence and radial-azimuthal phase separation. The ground-state phase diagram, as well as the rotational properties, including the (meta)stability of currents in this system, is analyzed.

DOI: 10.1103/physreva.81.013630

Related papers

Spin-orbit-coupled Bose-Einstein condensates confined in concentrically coupled annular traps

Xiao-Fei Zhang, Ruifang Dong, Tao Liu +2 more

We investigate the ground state of spin-orbit-coupled Bose-Einstein condensates confined in concentrically coupled annular traps within the full parameter space accounts for all the nonlinear two-body collisions and the spin-orbit coupling. We find that depending on the ratio between interaction parameters and the strength of spin-orbit coupling, this coupled system presents various ground-state phases. Moreover, phase transition between radial phase separation and azimuthal phase separation can be induced by varying the strength of spin-orbit coupling when the system is first in radial phase separation, while phase transition between phase coexistence and azimuthal phase separation can also be realized through spin-orbit coupling when the system is first in phase coexistence. Finally, the spin texture is studied and the results show that the meron-antimeron pair spontaneously appears as the ground state of this coupled system. We also give an experimental protocol to observe these phenomena in future experiments.

Physical Review ADec 26, 201239 citations

Two-component dipolar Bose-Einstein condensate in concentrically coupled annular traps

Xiao-Fei Zhang, Wei Han, Lin Wen +4 more

Dipolar Bosonic atoms confined in external potentials open up new avenues for quantum-state manipulation and will contribute to the design and exploration of novel functional materials. Here we investigate the ground-state and rotational properties of a rotating two-component dipolar Bose-Einstein condensate, which consists of both dipolar bosonic atoms with magnetic dipole moments aligned vertically to the condensate and one without dipole moments, confined in concentrically coupled annular traps. For the nonrotational case, it is found that the tunable dipolar interaction can be used to control the location of each component between the inner and outer rings, and to induce the desired ground-state phase. Under finite rotation, it is shown that there exists a critical value of rotational frequency for the nondipolar case, above which vortex state can form at the trap center, and the related vortex structures depend strongly on the rotational frequency. For the dipolar case, it is found that various ground-state phases and the related vortex structures, such as polygonal vortex clusters and vortex necklaces, can be obtained via a proper choice of the dipolar interaction and rotational frequency. Finally, we also study and discuss the formation process of such vortex structures.

Scientific ReportsMar 3, 201529 citations

Phase separation in a mixture of charged Bose-Einstein condensates

Serdar Aksu, Nader Ghazanfari

We study the phase separation configurations and their rotational properties for a mixture of two interacting charged Bose-Einstein condensates subject to a magnetic field trapped in disc and Corbino geometries. We calculate the ground state energies of azimuthal and radial phase separation configurations using the Gross-Pitaevskii and the Thomas-Fermi approximations. We show that the results for experimentally relevant system parameters from both approaches are in good agreement. The immiscible mixture in both geometries with equal intracomponent interactions favors the azimuthal phase separation for any intercomponent interactions. Only an imbalance in the intracomponent interactions can result in a transition to the radial phase separation, for which the transition becomes sensitive to the shape of the trap. We present phase diagrams as function of the inter and intracomponent interactions. While the radial phase separation is widely favoured in disc geometry, the azimuthal phase separation is favoured for narrower Corbino geometries. We explore the rotational properties of the spatially separated condensates under the magnetic field, studying their angular momenta and velocity fields. The quantization of circulation breaks down for the azimuthal phase separation. In this case, the bulk region of the condensate continues to display superfluid flow behavior whereas the velocity field shows a rigid body behavior along the phase boundaries.

May 16, 20200 citations

Persistent currents in Bose gases confined in annular traps

S. Bargi, Francesc Malet, G. M. Kavoulakis +1 more

We examine the problem of stability of persistent currents in a mixture of two Bose gases trapped in an annular potential. We evaluate the critical coupling for metastability in the transition from quasi-one- to two-dimensional motion. We also evaluate the critical coupling for metastability in a mixture of two species as a function of the population imbalance. The stability of the currents is shown to be sensitive to the deviation from one-dimensional motion.

arXiv:1009.1599Physical Review AOct 28, 201031 citations

Phase separation in a mixture of trapped charged Bose–Einstein condensates

S Seyyare Aksu, A. Levent Subaşı, Nader Ghazanfari

Abstract We study the phase separation configurations and rotational properties of a mixture of two interacting charged Bose–Einstein condensates subjected to a magnetic field trapped in disc and Corbino geometries. We calculate the ground state energies of the azimuthal and radial phase separation configurations using the Gross–Pitaevskii and Thomas–Fermi approximations. We show that the results for the experimentally relevant system parameters of both approaches are in good agreement. For both geometries, an immiscible mixture with equal intracomponent interactions favors azimuthal phase separation for all intercomponent interactions. Only an imbalance in the intracomponent interactions can result in a transition to radial phase separation, for which the transition becomes sensitive to the shape of the trap. We present phase diagrams as functions of the inter- and intracomponent interactions. While radial phase separation is widely favoured in disc geometry, the azimuthal phase separation is favoured for narrower Corbino geometries. We explore the rotational properties of spatially separated condensates subjected to magnetic fields, studying their angular momenta and velocity fields. The quantization of circulation breaks down for azimuthal phase separation. In this case, the bulk region of the condensate continues to display superfluid flow behaviour, whereas the velocity field shows a rigid body behaviour along the phase boundaries.

arXiv:2005.08055Journal of Physics B Atomic Molecular and Optical PhysicsJan 10, 20212 citations

Ground state of a two-component dipolar Bose-Einstein condensate confined in a coupled annular potential

Zhang Xiao-Fei, Pei Zhang, Guangping Chen +3 more

By using the imaginary-time propagation method, we study the ground state structure of a two-component dipolar Bose-Einstein condensate confined in a coupled annular potential. The effects of contact and dipole-dipole interaction on the ground state density distribution of such a system are investigated in detail. The results show that the dipole-dipole interaction, acting as a new degree of freedom, can be used to obtain the desired ground state phases, and to control the phase transition between different ground states.

Acta Physica SinicaJan 1, 20153 citations