17 research outputs found
Dissipative dynamics of vortex arrays in anisotropic traps
We discuss the dissipative dynamics of vortex arrays in trapped
Bose-condensed gases and analyze the lifetime of the vortices as a function of
trap anisotropy and the temperature. In particular, we distinguish the two
regimes of the dissipative dynamics, depending on the relative strength of the
mutual friction between the vortices and the thermal component, and the
friction of the thermal particles on the trap anisotropy. We study the effects
of heating of the thermal cloud by the escaping vortices on the dynamics of the
system.Comment: RevTeX, 8 pages, 3 eps figure
Dissipative dynamics of vortex arrays in trapped Bose-condensed gases: neutron stars physics on K scale
We develop a theory of dissipative dynamics of large vortex arrays in trapped
Bose-condensed gases. We show that in a static trap the interaction of the
vortex array with thermal excitations leads to a non-exponential decay of the
vortex structure, and the characteristic lifetime depends on the initial
density of vortices. Drawing an analogy with physics of pulsar glitches, we
propose an experiment which employs the heating of the thermal cloud in the
course of the decay of the vortex array as a tool for a non-destructive study
of the vortex dynamics.Comment: 4 pages, revtex; revised versio
Dissipative dynamics of a kink state in a Bose-condensed gas
We develop a theory of dissipative dynamics of a kink state in a
finite-temperature Bose-condensed gas. We find that due to the interaction with
the thermal cloud the kink state accelerates towards the velocity of sound and
continuously transforms to the ground-state condensate. We calculate the
life-time of a kink state in a trapped gas and discuss possible experimental
implications.Comment: 4 pages, RevTe
Greying of the Dark Soliton: Depletion in the Anomalous Mode of the Bogoliubov Theory
Quantum depletion from an atomic quasi one dimensional Bose-Einstein
condensate with a dark soliton is studied in a framework of the Bogoliubov
theory. Depletion is dominated by an anomalous mode localized in a notch of the
condensate wave function. Depletion in the anomalous mode requires different
treatment than depletion without anomalous modes. In particular, quantum
depletion in the Bogoliubov vacuum of the anomalous mode is experimentally
irrelevant. A dark soliton is initially prepared in a state with minimal
depletion which is not a stationary state of the Bogoliubov theory. The notch
fills up with incoherent atoms depleted from the condensate. For realistic
parameters the filling time can be as short as 10 ms.Comment: 5 pages, version to appear in Phys.Rev.
Many-body solitons in a one-dimensional condensate of hard core bosons
A mapping theorem leading to exact many-body dynamics of impenetrable bosons
in one dimension reveals dark and gray soliton-like structures in a toroidal
trap which is phase-imprinted. On long time scales revivals appear that are
beyond the usual mean-field theory
Watching dark solitons decay into vortex rings in a Bose-Einstein condensate
We have created spatial dark solitons in two-component Bose-Einstein
condensates in which the soliton exists in one of the condensate components and
the soliton nodal plane is filled with the second component. The filled
solitons are stable for hundreds of milliseconds. The filling can be
selectively removed, making the soliton more susceptible to dynamical
instabilities. For a condensate in a spherically symmetric potential, these
instabilities cause the dark soliton to decay into stable vortex rings. We have
imaged the resulting vortex rings.Comment: 4 pages, 4 figure
A method for collective excitation of Bose-Einstein condensate
It is shown that by an appropriate modification of the trapping potential one
may create collective excitation in cold atom Bose-Einstein condensate. The
proposed method is complementary to earlier suggestions. It seems to be
feasible experimentally --- it requires only a proper change in time of the
potential in atomic traps, as realized in laboratories already.Comment: 4 pages, 4 figures; major revision, several references added,
interacting particles case adde
Vortex nucleation through edge states in finite Bose-Einstein condensates
We study the vortex nucleation in a finite Bose-Einstein condensate. Using a
set of non-local and chiral boundary conditions to solve the
Schrdinger equation of non-interacting bosons in a rotating trap, we
obtain a quantitative expression for the characteristic angular velocity for
vortex nucleation in a condensate which is found to be 35% of the transverse
harmonic trapping frequency.Comment: 24 pages, 8 figures. Both figures and the text have been revise