arXiv subjects

R. Fiore

Publications and source records attributed to R. Fiore.

99 records · Page 6Linked to original sources

arXiv1995

Lattice effective potential of massless $(λΦ^4)_4$: `triviality' and spontaneous symmetry breaking

We present a precise lattice computation of the slope of the effective potential for massless $(λΦ^4)_4$ theory in the region of bare parameters indicated by the Brahm's analysis of lattice data. Our results confirm the existence on the lattice of a remarkable phase of $(λΦ^4)_4$ where Spontaneous Symmetry Breaking is generated through ``dimensional transmutation''. The resulting effective potential shows no evidence for residual self-interaction effects of the shifted `Higgs' field $h(x)=Φ(x)-\langleΦ\rangle$, as predicted by ``triviality'', and cannot be reproduced in perturbation theory. Accordingly the mass of the Higgs particle, by itself, does not represent a measure of any observable interaction.

hep-th↗

arXiv1994

Rough Interfaces Beyond the Gaussian Approximation

We compare predictions of the Capillary Wave Model with Monte Carlo results for the energy gap and the interface energy of the 3D Ising model in the scaling region. Our study reveals that the finite size effects of these quantities are well described by the Capillary Wave Model, expanded to two-loop order (one order beyond the Gaussian approximation).

hep-lat↗

arXiv1994

Rough Interfaces Beyond the Gaussian Approximation

We compare predictions of the Capillary Wave Model beyond its Gaussian approximation with Monte Carlo results for the energy gap and the surface energy of the 3D Ising model in the scaling region. Our study reveals that the finite size effects of these quantities are well described by the Capillary Wave Model, expanded to two--loop order ( one order beyond the Gaussian approximation).

hep-lat↗

arXiv1994

Quark contribution to the reggeon-reggeon-gluon vertex in QCD

The quark loop contribution to the reggeon-reggeon-gluon vertex is calculated in QCD, where the reggeon is the reggeized gluon. Compared with the vertex in the Born approximation, this contribution exhibits a new spin structure as well as the gluon loop one. A remarkable but not complete cancellation between gluon and quark contributions to this new spin structure takes place for the case of three massless quark flavours.

hep-th↗

arXiv1993

On the behaviour of spatial Wilson loops in the high temperature phase of Lattice Gauge Theories

The behaviour of the space-like string tension in the high temperature phase is studied. Data obtained in the $Z_2$ gauge model in (2+1) dimensions are compared with predictions of a simple model of a fluctuating flux tube with finite thickness. It is shown that in the high temperature phase contributions coming from the fluctuations of the flux tube vanish. As a consequence we also show that in (2+1) dimensional gauge theories the thickness of the flux tube coincides with the inverse of the deconfinement temperature.

hep-lat↗

arXiv1993

Radiative corrections to quark-quark-reggeon vertex in QCD

One loop corrections to the coupling of the reggeized gluon to quarks are calculated in QCD. Combining this result with the known corrections to the gluon-gluon-reggeon vertex, we check the self-consistency of the representation of the amplitudes with gluon quantum numbers and negative signature in the $t$-channel in terms of Regge pole contribution.

hep-ph↗

arXiv1993

Strings And Non-Topological Solitons

We have numerically calculated topological andnon-topological solitons in two spatial dimensions with Chern-Simons term. Their quantum stability, as well as that of the Maxwell vortex, is analyzed by means of bounce instantons which involve three-dimensional strings and non-topological solitons.

hep-th↗

arXiv1992

The Effective String of 3D Z_2 Gauge Theory as a c=1 compactified CFT

We report on a high precision Montecarlo test of the three dimensional Ising gauge model at finite temperature. The string tension $σ$ is extracted from the expectation values of correlations of Polyakov lines. Agreement with the string tension extracted from Wilson loops is found only if the quantum fluctuations of the flux tube are properly taken into account. The central charge of the underlying conformal field theory is c=1.

hep-lat↗

arXiv1991

Critical Boundary Conditions for the Effective String

Gauge systems in the confining phase induce constraints at the boundaries of the effective string, which rule out the ordinary bosonic string even with short distance modifications. Allowing topological excitations, corresponding to winding around the colour flux tube, produces at the quantum level a universal free fermion string with a boundary phase nu=1/4. This coincides with a model proposed some time ago in order to fit Monte Carlo data of 3D and 4D Lattice gauge systems better. A universal value of the thickness of the colour flux tube is predicted.

hep-th↗