Condensed Fermi systems with an odd number of particles
can be described by means of polarizing
external fields having a time-odd character. We illustrate how this
works for Fermi gases and atomic nuclei treated by density functional theory
or Hartree-Fock-Bogoliubov (HFB) theory.
We discuss the method based on introducing two chemical potentials
for different superfluid components, whereby one may change the
particle-number parity of the underlying quasiparticle vacuum.
Formally, this method is a variant of non-collective cranking,
and the procedure is equivalent to the so-called
blocking. We present and exemplify relations between the two-chemical-potential
method and the cranking approximation for Fermi gases and nuclei.
George Bertsch,
Jacek Dobaczewski,
Witold Nazarewicz,
Junchen Pei
April 13, 2009
