13,760 research outputs found
Ultradilute low-dimensional liquids
We calculate the energy of one- and two-dimensional weakly interacting
Bose-Bose mixtures analytically in the Bogoliubov approximation and by using
the diffusion Monte Carlo technique. We show that in the case of attractive
inter- and repulsive intraspecies interactions the energy per particle has a
minimum at a finite density corresponding to a liquid state. We derive the
Gross-Pitaevskii equation to describe droplets of such liquids and solve it
analytically in the one-dimensional case.Comment: published version + supplemental materia
Scattering properties of weakly bound dimers of fermionic atoms
We consider weakly bound diatomic molecules (dimers) formed in a
two-component atomic Fermi gas with a large positive scattering length for the
interspecies interaction. We develop a theoretical approach for calculating
atom-dimer and dimer-dimer elastic scattering and for analyzing the inelastic
collisional relaxation of the molecules into deep bound states. This approach
is based on the single-channel zero range approximation, and we find that it is
applicable in the vicinity of a wide two-body Feshbach resonance. Our results
draw prospects for various interesting manipulations of weakly bound dimers of
fermionic atoms.Comment: extended version of cond-mat/030901
Crystalline phase of strongly interacting Fermi mixtures
We show that the system of weakly bound molecules of heavy and light
fermionic atoms is characterized by a long-range intermolecular repulsion and
can undergo a gas-crystal quantum transition if the mass ratio exceeds a
critical value. For the critical mass ratio above 100 obtained in our
calculations, this crystalline order can be observed as a superlattice in an
optical lattice for heavy atoms with a small filling factor. We also find that
this novel system is sufficiently stable with respect to molecular relaxation
into deep bound states and to the process of trimer formation.Comment: 4 pages, 1 color figure, published versio
Equilibrium and dynamics of a trapped superfluid Fermi gas with unequal masses
Interacting Fermi gases with equal populations but unequal masses are
investigated at zero temperature using local density approximation and the
hydrodynamic theory of superfluids in the presence of harmonic trapping.
We derive the conditions of energetic stability of the superfluid
configuration with respect to phase separation and the frequencies of the
collective oscillations in terms of the mass ratio and the trapping frequencies
of the two components. We discuss the behavior of the gas after the trapping
potential of a single component is switched off and show that, near a Feshbach
resonance, the released component can still remain trapped due to many-body
interaction effects. Explicit predictions are presented for a mixture of Li
and K with resonant interaction.Comment: 4 pages, 2 figure
Stable dilute supersolid of two-dimensional dipolar bosons
We consider two-dimensional bosonic dipoles oriented perpendicularly to the
plane. On top of the usual two-body contact and long-range dipolar interactions
we add a contact three-body repulsion as expected, in particular, for dipoles
in the bilayer geometry with tunneling. The three-body repulsion is crucial for
stabilizing the system, and we show that our model allows for stable continuous
space supersolid states in the dilute regime and calculate the zero-temperature
phase diagram.Comment: revised version, 5 pages, 2 figures, with 3 pages supplementary
materia
Three-boson problem near a narrow Feshbach resonance
We consider a three-boson system with resonant binary interactions and show
that three-body observables depend only on the resonance width and the
scattering length. The effect of narrow resonances is qualitatively different
from that of wide resonances revealing novel physics of three-body collisions.
We calculate the rate of three-body recombination to a weakly bound level and
the atom-dimer scattering length and discuss implications for experiments on
Bose-Einstein condensates and atom-molecule mixtures near Feshbach resonances.Comment: published versio
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