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21.
Bivash R Behera Subinit Roy P Basu M K Sharan S Jena M Satpathy SK Datta L Satpathy ML Chatterjee 《Pramana》1999,53(3):563-566
Time of flight and energy of fission fragments were measured using pulsed beam. Fission fragment mass and energy integrated
angular distributions were extracted. Fission fragment anisotropy was explained in the framework of saddle point model. 相似文献
22.
One-dimensional (1D) dipolar quantum gases are characterized by a very special condition where super-strong correlations occur to significantly affect the static and dynamical low-energy behavior. This behavior is accurately described by the Luttinger Liquid theory with parameter K < 1. Dipolar Bose gases are routinely studied in laboratory with Chromium atoms. On the other hand, 1D realizations with molecular quantum gases can be at reach of current experimental expertises, allowing to explore such extreme quantum degenerate conditions which are the bottom line for designing technological devices. Aim of the present contribution is to focus on the possible probes expected to signal the reach of Luttinger-Liquid behavior in 1D dipolar gases. 相似文献
23.
We predict a direct and observable signature of the superfluid phase in a quantum Fermi gas, in a temperature regime already accessible in current experiments. We apply the theory of resonance superfluidity to a gas confined in a harmonic potential and demonstrate that a significant increase in density will be observed in the vicinity of the trap center. 相似文献
24.
We consider the superfluid phase transition that arises when a Feshbach resonance pairing occurs in a dilute Fermi gas. We apply our theory to consider a specific resonance in potassium ((40)K), and find that for achievable experimental conditions, the transition to a superfluid phase is possible at the high critical temperature of about 0.5T(F). Observation of superfluidity in this regime would provide the opportunity to experimentally study the crossover from the superfluid phase of weakly coupled fermions to the Bose-Einstein condensation of strongly bound composite bosons. 相似文献
25.
M.L. Chiofalo M. Polini M.P. Tosi 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,11(3):371-378
We study the dispersion relation of the excitations of a dilute Bose-Einstein condensate confined in a periodic optical potential
and its Bloch oscillations in an accelerated frame. The problem is reduced to one-dimensionality through a renormalization
of the s-wave scattering length and the solution of the Bogolubov-de Gennes equations is formulated in terms of the appropriate Wannier
functions. Some exact properties of a periodic one-dimensional condensate are easily demonstrated: (i) the lowest band at
positive energy refers to phase modulations of the condensate and has a linear dispersion relation near the Brillouin zone
centre; (ii) the higher bands arise from the superposition of localized excitations with definite phase relationships; and
(iii) the wavenumber-dependent current under a constant force in the semiclassical transport regime vanishes at the zone boundaries.
Early results by Slater [Phys. Rev. 87, 807 (1952)] on a soluble problem in electron energy bands are used to specify the conditions under which the Wannier functions
may be approximated by on-site tight-binding orbitals of harmonic-oscillator form. In this approximation the connections between
the low-lying excitations in a lattice and those in a harmonic well are easily visualized. Analytic results are obtained in
the tight-binding scheme and are illustrated with simple numerical calculations for the dispersion relation and semiclassical
transport in the lowest energy band, at values of the system parameters which are relevant to experiment.
Received 3 December 1999 and Received in final form 22 March 2000 相似文献