Twisted condensates of quantised fields

by F. Gallone, A. Sparzani, R. F. Streater and C. Ubertone; J. Phys., A19, 241-258, 1986.

ABSTRACT

We construct some quasi-free pure states of free quantised fields in (1+1)-dimensions, that are locallised in the sense of Knight. We consider massless or massive Dirac fields forming a U(n)-multiplet, n\geq 1, and subject it to a local gauge transformation. We also subject a doublet of massive Klein-Gordon fields to local SO(2) transformations. We find the conditions that the resulting automorphisms are spatial in Fock space. In some cases the conditions turn out to require that certain parameters, identified as the winding numbers of the gauge, are integers. It is argued that this integer labels states of various charge.