64 research outputs found
Ground-state properties of interacting two-component Bose gases in a one-dimensional harmonic trap
We study ground-state properties of interacting two-component boson gases in
a one-dimensional harmonic trap by using the exact numerical diagonalization
method. Based on numerical solutions of many-body Hamiltonians, we calculate
the ground-state density distributions in the whole interaction regime for
different atomic number ratio, intra- and inter-atomic interactions. For the
case with equal intra- and inter-atomic interactions, our results clearly
display the evolution of density distributions from a Bose condensate
distribution to a Fermi-like distribution with the increase of the repulsive
interaction. Particularly, we compare our result in the strong interaction
regime to the exact result in the infinitely repulsive limit which can be
obtained by a generalized Bose-Fermi mapping. We also discuss the general case
with different intra- and inter-atomic interactions and show the rich
configurations of the density profiles.Comment: 6 pages, 5 figures, references adde
Quantum dynamics of repulsively bound atom pairs in the Bose-Hubbard model
We investigate the quantum dynamics of repulsively bound atom pairs in an
optical lattice described by the periodic Bose-Hubbard model both analytically
and numerically. In the strongly repulsive limit, we analytically study the
dynamical problem by the perturbation method with the hopping terms treated as
a perturbation. For a finite-size system, we numerically solve the dynamic
problem in the whole regime of interaction by the exact diagonalization method.
Our results show that the initially prepared atom pairs are dynamically stable
and the dissociation of atom pairs is greatly suppressed when the strength of
the on-site interaction is much greater than the tunneling amplitude, i.e., the
strongly repulsive interaction induces a self-localization phenomenon of the
atom pairs.Comment: 7 pages, 6 figures, significant changes mad
Preparation of stable excited states in an optical lattice via sudden quantum quench
We study how stable excited many-body states of the Bose-Hubbard model,
including both the gas-like state for strongly attractive bosons and bound
cluster state for repulsive bosons, can be produced with cold bosonic atoms in
an one-dimensional optical lattice. Starting from the initial ground states of
strongly interacting bosonic systems, we can achieve stable excited states of
the systems with opposite interaction strength by suddenly switching the
interaction to the opposite limit. By exactly solving dynamics of the
Bose-Hubbard model, we demonstrate that the produced excited state can be a
very stable dynamic state. This allows the experimental study of excited state
properties of ultracold atoms system in optical lattices.Comment: 5 pages, 4 figure
The lowest scattering state of one-dimensional Bose gas with attractive interactions
We investigate the lowest scattering state of one-dimensional Bose gas with
attractive interactions trapped in a hard wall trap. By solving the Bethe
ansatz equation numerically we determine the full energy spectrum and the exact
wave function for different attractive interaction parameters. The resultant
density distribution, momentum distribution, reduced one body density matrix
and two body correlation show that the decreased attractive interaction induces
rich density profiles and specific correlation properties in the weakly
attractive Bose gas.Comment: 6 pages, 6figure
Transition from Tonks-Girardeau gas to super-Tonks-Girardeau gas as an exact many-body dynamics problem
We investigate transition of a one-dimensional interacting Bose gas from a
strongly repulsive regime to a strongly attractive regime, where a stable
highly excited state known as the super Tonks-Girardeau gas was experimentally
realized very recently. By solving exact dynamics of the integrable
Lieb-Liniger Bose gas, we demonstrate that such an excited gas state can be a
very stable dynamic state. Furthermore we calculate the breathing mode of the
super Tonks-Girardeau gas which is found to be in good agreement with
experimental observation. Our results show that the highly excited super
Tonks-Girardeau gas phase can be well understood from the fundamental theory of
the solvable Bose gas.Comment: 4 pages, 4 figures, version to appear in Phys. Rev. A as a Rapid
Communicatio
Non-gapless excitation and zero-bias fast oscillations in the LDOS of surface superconducting states
Recently a novel surface pair-density-wave (PDW) superconducting state has
been discovered in Refs. [Phys. Rev. Lett. \textbf{122}, 165302 (2019)] and
Phys. Rev. B \textbf{101}, 054506 (2020)], which may go through a distinct
multiple phase transition (MPT) when the superconductivity fades away from bulk
to the boundary (e.g. edges and corners). Based on the Bogoliubov-de Gennes
equations for the attractive tight-binding Hubbard modal in a one-dimensional
chain, we demonstrate that the surface PDW state has a non-gapless
quasiparticle spectrum, which is contrary to the conventional surface
superconducting state. Moreover, we find that the MPT is associated with a
zero-bias fast oscillating pattern in the LDOS near the surface. Our findings
provide a potential experimental clue to identify the surface PDW state.Comment: 4 figure
Ground-state properties of one-dimensional ultracold Bose gases in a hard-wall trap
We investigate the ground state of the system of N bosons enclosed in a
hard-wall trap interacting via a repulsive or attractive -function
potential. Based on the Bethe ansatz method, the explicit ground state wave
function is derived and the corresponding Bethe ansatz equations are solved
numerically for the full physical regime from the Tonks limit to the strongly
attractive limit. It is shown that the solution takes different form in
different regime. We also evaluate the one body density matrix and second-order
correlation function of the ground state for finite systems. In the Tonks limit
the density profiles display the Fermi-like behavior, while in the strongly
attractive limit the Bosons form a bound state of N atoms corresponding to the
N-string solution. The density profiles show the continuous crossover behavior
in the entire regime. Further the correlation function indicates that the Bose
atoms bunch closer as the interaction constant decreases.Comment: 7 pages, 6 figures, version published in Phys. Rev.
- …