Andr F. Verbeure
The Condensate Equation for non-homogeneous Bosons
(202K, pdf)

ABSTRACT.  We consider Boson systems with non-ground state $(q \neq 
0)$-condensation. This phenomenon is accompanied with spontaneous 
breaking of the translation symmetry down to a lattice symmetry as 
well as of the gauge symmetry. We give a general and rigorous 
derivation of the condensate equation for these systems. We 
discuss model applications.