1,329 research outputs found
Exploring the Dynamics of Three-Dimensional Lattice Gauge Theories by External Fields
We investigate the dynamics of three-dimensional lattice gauge theories by
means of an external Abelian magnetic field. For the SU(2) lattice gauge theory
we find evidence of the unstable modes.Comment: 3 pages, PostScript. Contribution to the LATTICE 93 Conference
(Dallas, U.S.A., September 1993) preprint BARI-TH-162/9
Investigations on the deconfining phase transition in QCD
We investigate the deconfining phase transition in SU(3) pure gauge theory
and in full QCD with two flavors of staggered fermions by means of a gauge
invariant thermal partition functional. In the pure gauge case our finite size
scaling analysis is in agreement with the well known weak first order phase
transition. In the case of 2 flavors full QCD we find that the phase transition
is consistent with weak first order, contrary to the expectation of a crossover
for not too large quark masses.Comment: 3 pages, 3 figures, Lattice2003(topology
Indications on the Higgs boson mass from lattice simulations
The `triviality' of has been traditionally interpreted within
perturbation theory where the prediction for the Higgs boson mass depends on
the magnitude of the ultraviolet cutoff . This approach crucially
assumes that the vacuum field and its quantum fluctuations rescale in the same
way. The results of the present lattice simulation, confirming previous
numerical indications, show that this assumption is not true. As a consequence,
large values of the Higgs mass can coexist with the limit . As an example, by extrapolating to the Standard Model our results
obtained in the Ising limit of the one-component theory, one can obtain a value
as large as GeV, independently of .Comment: 3 pages, 2 figures, Lattice2003(higgs
Generalized Gaussian Effective Potential: Low Dimensional Scalar Fields
We study a generalization of the Gaussian effective potential for
self-interacting scalar fields in one and two spatial dimensions. We compute
the two-loop corrections and discuss the renormalization of the generalized
Gaussian effective potential.Comment: tex, 10 pages + 4 Postscript figures include
On the Meissner effect in SU(2) lattice gauge theory
We investigate the dual superconductor model of color confinement in SU(2)
lattice gauge theory. We find that the transverse distribution of the
longitudinal chromoelectric field between static quarks displays the dual
Meissner effect. We also give evidence that the problem of color confinement
could be approached in the framework of the 't~Hooft's Abelian projection.Comment: 3 pages, PostScript. Contribution to the LATTICE 93 Conference
(Dallas, U.S.A., September 1993) preprint BARI-TH-161/9
Nature and Raman signatures of the Higgs amplitude mode in the coexisting superconducting and charge-density-wave state
We investigate the behavior of the Higgs (amplitude) mode when
superconductivity emerges on a preexisting charge-density-wave state. We show
that the weak overdamped square-root singularity of the amplitude fluctuations
in a standard BCS superconductor is converted in a sharp, undamped power-law
divergence in the coexisting state, reminiscent of the Higgs behavior in
Lorentz-invariant theories. This effect reflects in a strong superconducting
resonance in the Raman spectra, both for an electronic and a phononic mechanism
leading to the Raman visibility of the Higgs. In the latter case, our results
are relevant to the interpretation of the Raman spectra measured experimentally
in NbSe2.Comment: Extended version, accepted for publication in PR
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