Superfluid states with moving condensate in nuclear matter

Superfluid states of symmetric nuclear matter with finite total momentum of Cooper pairs (nuclear LOFF phase) are studied with the use of Fermi-liquid theory in the model with Skyrme effective forces. It is considered the case of four-fold splitting of the excitation spectrum due to finite superfluid momentum and coupling of T=0 and T=1 pairing channels. It has been shown that at zero temperature the energy gap in triplet-singlet (TS) pairing channel (in spin and isospin spaces) for the SkM$^*$ force demonstrates double-valued behavior as a function of superfluid momentum. As a consequence, the phase transition at the critical superfluid momentum from the LOFF phase to the normal state will be of a first order. Behavior of the energy gap as a function of density for TS pairing channel under increase of superfluid momentum changes from one-valued to universal two-valued. It is shown that two-gap solutions, describing superposition of states with singlet-triplet (ST) and TS pairing of nucleons appear as a result of branching from one-gap ST solution. Comparison of the free energies shows that the state with TS pairing of nucleons is thermodynamically most preferable.Comment: Report on DAAD summer school "Dense matter in Particle- and Astrophysics". Prepared with RevTeX4, 5p., 4 eps figure

Interpretation of infrared spectra of chalcogenide glasses Se95As5 impurited by samarium

In work investigated with method IR of spectroscopy of amorphous selenium andsystem Se95As5 containing impurity samarium. It is certain that, in IR a spectrum of amorphous selenium due to hypervalent defects maxima with different intensity are observed in 230 and 270 cm-1.Increase of the concentration of impurity samarium in spectrum Se95As5, the maximum arises with 400cm-1frequency which, are connected with SmSe3 structural elements

Superfluidity of a condensate with np pairing correlations in asymmetric nuclear matter

Influence of asymmetry on superfluidity of nuclear matter with triplet-singlet pairing of nucleons (in spin and isospin spaces) is considered within the framework of a Fermi-liquid theory. Solutions of self-consistent equations for the energy gap at T=0 are obtained. It is shown, that if the chemical potentials of protons and neutrons are determined in the zero gap width approximation, then the energy gap for some values of density and asymmetry parameter of nuclear matter demonstrates double-valued behavior. However, with account for the feedback of pairing correlations through the normal distribution functions of nucleons two-valued behavior of the energy gap turns into universal one-valued behavior. At T=0 the energy gap has a discontinuities as a function of density in a narrow layer model. These discontinuities depend on the asymmetry parameter

BCS and BEC p-wave pairing in Bose-Fermi gases

The pairing of fermionic atoms in a mixture of atomic fermion and boson gases at zero temperature is investigated. The attractive interaction between fermions, that can be induced by density fluctuations of the bosonic background, can give rise to a superfluid phase in the Fermi component of the mixture. The atoms of both species are assumed to be in only one internal state, so that the pairing of fermions is effective only in odd-l channels. No assumption about the value of the ratio between the Fermi velocity and the sound velocity in the Bose gas is made in the derivation of the energy gap equation. The gap equation is solved without any particular "ansatz" for the pairing field or the effective interaction. The p-wave superfluidity is studied in detail. By increasing the strength and/or decreasing the range of the effective interaction a transition of the fermion pairing regime, from the Bardeen-Cooper-Schrieffer state to a system of tightly bound couples can be realized. These composite bosons behave as a weakly-interacting Bose-Einstein condensate.Comment: 14 pages, 6 eps-figures. To be published in European Physical Journal