2,546 research outputs found
Zero Point Energy of Renormalized Wilson Loops
The quark antiquark potential, and its associated zero point energy, can be
extracted from lattice measurements of the Wilson loop. We discuss a unique
prescription to renormalize the Wilson loop, for which the perturbative
contribution to the zero point energy vanishes identically. A zero point energy
can arise nonperturbatively, which we illustrate by considering effective
string models. The nonperturbative contribution to the zero point energy
vanishes in the Nambu model, but is nonzero when terms for extrinsic curvature
are included. At one loop order, the nonperturbative contribution to the zero
point energy is negative, regardless of the sign of the extrinsic curvature
term.Comment: 14 pages, ReVTeX. Paper shortened, results unchange
Pauli-Fierz model with Kato-class potentials and exponential decays
Generalized Pauli-Fierz Hamiltonian with Kato-class potential \KPF in
nonrelativistic quantum electrodynamics is defined and studied by a path
measure. \KPF is defined as the self-adjoint generator of a strongly
continuous one-parameter symmetric semigroup and it is shown that its bound
states spatially exponentially decay pointwise and the ground state is unique.Comment: We deleted Lemma 3.1 in vol.
No-Go Theorem for Critical Phenomena in Large-Nc QCD
We derive some rigorous results on the chiral phase transition in QCD and
QCD-like theories with a large number of colors, Nc, based on the QCD
inequalities and the large-Nc orbifold equivalence. We show that critical
phenomena and associated soft modes are forbidden in flavor-symmetric QCD at
finite temperature T and finite but not so large quark chemical potential \mu
for any nonzero quark mass. In particular, the critical point in QCD at a
finite baryon chemical potential \mu_B = Nc\mu is ruled out, if the coordinate
(T, \mu) is outside the pion condensed phase in the corresponding phase diagram
of QCD at a finite isospin chemical potential \mu_I = 2\mu.Comment: 5 pages, 1 figure; published versio
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