Phase Transitions in Fermi Systems

Börje Johansson

Wolfgang Weller

W Weller

V.V. Mazepus

VICTOR A. KHODEL

A topological crossover, associated with the collapse of the Fermi surface in strongly correlated Fermi systems, is examined. It is demonstrated that in these systems, the temperature domain where standard Fermi liquid results hold dramatically narrows, because the Landau regime is replaced by a classical one. The impact of the collapse of the Fermi surface on pairing correlations is analyzed. In the domain of the Lifshitz phase diagram where the Fermi surface collapses, splitting of the BCS superconducting phase transition into two different ones of the same symmetry is shown to occur.

Shuai Yang, M. Al-Amri, Muhammad Suhail Zubairy

A quantum-degenerate Fermi gas in an optical cavity is investigated. It is shown that there exists a self-organization phase transition. This phase transition can be identified as the Dicke quantum phase transition. This investigation opens the door to include degenerate Fermi gases in the group of atomic systems which exhibit a self-organization threshold.