4,456 research outputs found
Collective modes of a harmonically trapped one-dimensional Bose gas: the effects of finite particle number and nonzero temperature
Following the idea of the density functional approach, we develop a
generalized Bogoliubov theory of an interacting Bose gas confined in a
one-dimensional harmonic trap, by using a local chemical potential - calculated
with the Lieb-Liniger exact solution - as the exchange energy. At zero
temperature, we use the theory to describe collective modes of a
finite-particle system in all interaction regimes from the ideal gas limit, to
the mean-field Thomas-Fermi regime, and to the strongly interacting
Tonks-Girardeau regime. At finite temperature, we investigate the temperature
dependence of collective modes in the weak-coupling regime by means of a
Hartree-Fock-Bogoliubov theory with Popov approximation. By emphasizing the
effects of finite particle number and nonzero temperature on collective mode
frequencies, we make comparisons of our results with the recent experimental
measurement [E. Haller et al., Science 325, 1224 (2009)] and some previous
theoretical predictions. We show that the experimental data are still not fully
explained within current theoretical framework.Comment: 10 pages, 8 figure
Light-Cone Sum Rules Analysis of Weak Decays
In this work, we investigate the semi-leptonic weak decays of spin-1/2
doubly-heavy baryons into spin-3/2 singly-heavy baryons
within light-cone sum rules. Using the parallel
components of the light-cone distribution amplitudes of
, the transition form factors for these decays are
calculated both analytically and numerically. The numerical results for these
semi-leptonic weak decays widths and branching ratios are also predicted, which
are compared with the same predictions by other theoretical approaches in the
literatures. These phenomenology predictions can be tested by the experiments
in the future.Comment: 19 pages, 2 figures, 4 table
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