Gauge-invariant variational methods for Hamiltonian lattice gauge theories

摘要: This paper develops variational methods for calculating the ground-state and excited-state spectrum of Hamiltonian lattice gauge theories defined in A/sub 0/ = 0 gauge. The scheme introduced this has advantage allowing one to convert more familiar tools such as mean-field, Hartree-Fock, real-space renormalization-group approximation, which are by their very nature gauge-noninvariant methods, into fully gauge-invariant techniques. We show that these apply same way both Abelian non-Abelian theories, they at least powerful enough describe correctly physics periodic quantum electrodynamics (PQED) (2+1) (3+1) space-time dimensions. formulates problem shows how reduce Rayleigh-Ritz computing partition function a classical spin system. discuss evaluation effective derives PQED then ways carrying out system equivalent theory. explicit form theory is derived, but because considerably complicated than derived Abelianmore » no presented. However, comparing gauge-projected Hartree-Fock wave with pure SU(2) theory, we able extremely interesting differences emerge between even simple level. close discussion fermions can extend ideas allow computation glueball hadron spectrum.« less