arXiv subjects

P. Petreczky

Publications and source records attributed to P. Petreczky.

139 records · Page 8Linked to original sources

arXiv2000

Screening in Hot SU(2) Gauge Theory and Propagators in 3d Adjoint Higgs model

We investigate the large distance behavior of the electric and magnetic propagators of hot SU(2) gauge theory in different gauges using lattice simulations of the full 4d theory and the effective, dimensionally reduced 3d theory. A comparison of the 3d and 4d data for the propagators suggests that dimensional reduction works surprisingly well down to temperatures T=2 T_c. A detailed study of the volume dependence of magnetic propagators is performed. The electric propagators show exponential decay at large distances in all gauges considered and a possible gauge dependence of the electric screening mass turns out to be statistically insignificant.

hep-lat↗

arXiv2000

Percolation and Critical Behaviour in SU(2) Gauge Theory

The paramagnetic-ferromagnetic transition in the Ising model can be described as percolation of suitably defined clusters. We have tried to extend such picture to the confinement-deconfinement transition of SU(2) pure gauge theory, which is in the same universality class of the Ising model. The cluster definition is derived by approximating SU(2) by means of Ising-like effective theories. The geometrical transition of such clusters turns out to describe successfully the thermal counterpart for two different lattice regularizations of (3+1)-d SU(2).

hep-lat↗

arXiv1999

Coupled gap equations for the screening masses in the SU(2) Higgs model

The complete set of static screening masses is determined for the SU(2) Higgs model from one-loop coupled gap equations. Results from the version, containing scalar fields both in the fundamental and adjoint representations are compared with the model arising when the integration over the adjoint scalar field is performed. A non-perturbative and non-linear mapping between the couplings of the two models is proposed, which exhibits perfect decoupling of the heavy adjoint scalar field. Also the alternative of a gauge invariant mass resummation is investigated in the high temperature phase.

hep-ph↗

arXiv1999

Effective theory for the soft fluctuation modes in the spontaneously broken phase of the N-component scalar field theory

The effective dynamics of the low-frequency modes is derived for the O(N) symmetric scalar field theory in the broken symmetry phase. The effect of the high-frequency fluctuations is taken into account at one-loop level exactly. A new length scale is shown to govern the long-time asymptotics of the linear response function of the Goldstone modes. The large time asymptotic decay of an arbitrary fluctuation is determined in the linear regime. We propose a set of local equations for the numerical solution of the effective non-linear dynamics. The applicability of the usual gradient expansion is carefully assessed.

hep-ph↗

arXiv1999

Propagators of hot SU(2) gauge theory from 3d adjoint Higgs model

We study propagators of the lattice 3d adjoint Higgs model, considered as an effective theory of 4d SU(2) gauge theory at high temperature. The propagators are calculated in so-called lambda-gauges. From the long distance behaviour of the propagators we extract the screening masses. It is shown that the pole masses extracted from the propagators agree well with the screening masses obtained recently in finite temperature SU(2) theory. The gauge dependence of the screening masses is also discussed.

hep-lat↗

arXiv1999

Screening Masses of Hot SU(2) Gauge Theory from the 3D Adjoint Higgs Model

We study the Landau gauge propagators of the lattice SU(2) 3d adjoint Higgs model, considered as an effective theory of high temperature 4d SU(2) gauge theory. From the long distance behaviour of the propagators we extract the screening masses. It is shown that the pole masses extracted from the propagators agree well with the screening masses obtained recently in finite temperature SU(2) theory. The relation of the propagator masses to the masses extracted from gauge invariant correlators is also discussed. In so-called lambda gauges non-perturbative evidence is given for the gauge independence of pole masses within this class of gauges.

hep-ph↗

arXiv1998

QCD thermodynamics from 3d adjoint Higgs model

The screening masses of hot SU(N) gauge theory, defined as poles of the corresponding propagators are studied in 3d adjoint Higgs model, considered as an effective theory of QCD, using coupled gap equations and lattice Monte-Carlo simulations (for N=2). Using so-called lambda gauges non-perturbative evidence for gauge independence of the pole masses within this class of gauges is given. A possible application of the screening masses for the resummation of the free energy is discussed.

hep-ph↗

arXiv1998

Screening Masses of Hot SU(2) Gauge Theory from the 3d Adjoint Higgs Model

We study the Landau gauge propagators of the lattice SU(2) 3d adjoint Higgs model, considered as an effective theory of high temperature 4d SU(2) gauge theory. From the long distance behaviour of the propagators we extract the screening masses. The propagators are studied both in the symmetric and the broken phases of the 3d Higgs model. It is shown that the pole masses extracted from the propagators in the symmetric phase agree well with the screening masses obtained recently in finite temperature SU(2) theory, while propagators measured in the broken phase show quite a different behaviour. This suggest that the symmetric phase of the 3d model corresponds to the deconfined phase of the 4d SU(2) gauge theory. The relation of the propagator masses to the masses extracted from gauge invariant correlators and the mass gap of pure 3d SU(2) gauge theory is also discussed.

hep-lat↗

arXiv1998

Coupled Gap Equations for the Screening Masses in Hot SU(N) Gauge Theory

Coupled 1-loop gap equations are studied numerically for non-Abelian electric and magnetic screening in various versions of the three-dimensional effective gauge models. Corrections due to higher dimensional and non-local operators are assessed quantitatively. Comparison with numerical Monte-Carlo investigations suggests that quantitative understanding beyond the qualitative features can be achieved only by going beyond the present treatment.

hep-ph↗

arXiv1997

Screened Perturbation Theory

A new perturbative scheme is proposed for the evaluation of the free energy density of field theories at finite temperature. The screened loop expansion takes into account exactly the phenomenon of screening in thermal propagators.The approach is tested in the N-component scalar field theory at 2-loop level and also at 3-loop in the large $N$ limit. The perturbative series generated by the screened loop expansion shows much better numerical convergence than previous expansions generated in powers of the quartic coupling.

hep-ph↗

arXiv1996

U(1) Gauge Theory with Villain Action on Spherical Lattices

We have studied the U(1) gauge field theory with Villain (periodic Gaussian) action on spherelike lattices. The effective size of the systems studied ranges from 6 to 16. We do not observe any 2-state signal in the distribution function of the plaquette expectation value at the deconfining phase transition. The observed finite-size scaling behavior is consistent with a second order phase transition. The obtained value of the critical exponent is nu =0.366(12) and thus neither Gaussian (nu = 0.5) nor discontinuous (nu=0.25) type, indicating a nontrivial continuum limit.

hep-lat↗

arXiv1995

Controlling a Non-Polynomial Reduced Finite Temperature Action in the U(1) Higgs Model

An effective theory is constructed for the scalar electrodynamics via 2-loop integration over all non-static fields and the screened electric component of the vector-potential. Non-polynomial terms of the action are preserved and included into the 2-loop calculation of the effective potential of the reduced theory. Also the inclusion of some non-local terms is shown to be important. The effect of non-polynomial operators on the symmetry restoring phase transition is quantitatively compared to results from a local, superrenormalisable approximate effective theory.

hep-ph↗

arXiv1995

RENORMALISATION GROUP AIDED FINITE TEMPERATURE REDUCTION OF QUANTUM FIELD THEORIES

Dimensional reduction of finite temperature quantum field theories can be improved with help of continous renormalisation group steps. The method is applied to the integration of the lowest non-static ($n=\pm 1$) modes of the finite temperature $Φ^4$-theory. A second, physically important application is the integration of the Debye-screened ${\bf A_0}(x)$ static scalar potential in the gauged SU(2) Higgs model.

hep-ph↗