3 research outputs found
Vacuum structure of CP^N sigma models at theta=pi
We show that parity symmetry is not spontaneously broken in the CP^N sigma
model for any value of N when the coefficient of the --term becomes
(mod ). The result follows from a non-perturbative analysis
of the nodal structure of the vacuum functional . The dynamical role
of sphalerons turns out to be very important for the argument. The result
introduces severe constraints on the possible critical behavior of the models
at (mod ).Comment: 8 pages, revtex, to appear in Phys. Rev. Let
Vacuum Nodes in QCD at : Exact Results
We show that the vacuum functional of 3+1 dimensional non-abelian gauge
theories vanishes for some classical field configurations when
the coefficient of the CP violating --term becomes (mod.
). Some of these classical configurations are explicitly identified and
include sphalerons. The results shed new light into the non-perturbative
behavior of non-abelian gauge theories and suggest a relevant role for these
classical configurations in the confinement mechanism at .Comment: 11 pages, revte