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Chin. Phys.; (United States)

Phase transition in the two-level R(4) pairing force model

Gong-ou Xu, Li Fu-Li

Published Oct 1, 1986• 0 citations
OpenAlex

Abstract

The phase transition from the superfluid to normal state with an increase of the seniority number in the two-level pairing force model is studied with a boson-fermion composite representation. Criteria for identifying the phase transition with observable phase characteristics are discussed.

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Systems showing resonant superfluidity, driven by an exchange coupling of strength g between uncorrelated pairs of itinerant fermions and tightly bound ones, undergo a first-order phase transition as g increases beyond some critical value gc. The superfluid phase for g<or=gc is characterized by a gap in the fermionic single-particle spectrum and an acoustic sound-wave-like collective mode of the bosonic resonating fermion pairs inside this gap. For g>gc this state gives way to a phase-uncorrelated bosonic liquid with a q2 spectrum.
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