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Résumé |
We introduce a new fermionic variational wavefunction, suitable for
interacting multi-species systems of spinful fermions. This wavefunction
sustains superfluidity. In this frame, we also introduce a new quantum
index, which is related to the internal structure of the quantum state.
Applications include
quark matter, neutron stars, cold atoms and the high temperature
superconductors. Spin up and down fermions are, in principle,
inequivalent. Due to the inclusion of adequate 2-fermion correlations, a
wider class of Hamiltonians than sheer
Bardeen-Cooper-Schrieffer (BCS) type, comprising interaction and
hybridization between different fermion species, can be treated "exactly",
as in the well known manner of BCS theory. We present the finite
temperature version of the theory, and we discuss the appearance of charge
and spin density wave order. |
