arXiv subjects

B. J. Nauta

Publications and source records attributed to B. J. Nauta.

4 recordsLinked to original sources

arXiv2000

Transversality of the logarithmic divergences in the Classical Finite Temperature SU(N) Self-Energy

We show that the logarithmic divergences that appear in the classical approximation of the finite temperature SU(N) self-energy are transverse. We use the Ward identities in linear gauges and the fact that the superficial degree of divergence d of a classical diagram only depends on the number of loops l via d=2-l. We comment on the relevance of this result to the construction of a low-energy effective theory beyond HTLs.

hep-ph↗

arXiv1999

Counterterms for Linear Divergences in Real-Time Classical Gauge Theories at High Temperature

Real-time classical SU($N$) gauge theories at non-zero temperature contain linear divergences. We introduce counterterms for these divergences in the equations of motion in the continuum and on the lattice. These counterterms can be given in terms of auxiliary fields that satisfy local equations of motion. We present a lattice model with 6+1D auxiliary fields that for IR-sensitive quantities yields cut-off independent results to leading order in the coupling. Also an approximation with 5+1D auxiliary fields is discussed.

hep-ph↗

arXiv1999

Effective Classical Theory for Real-Time SU(N) Gauge Theories at High Temperature

We derive an effective classical theory for real-time SU($N$) gauge theories at high temperature. By separating off and integrating out quantum fluctuations we obtain a 3D classical path integral over the initial fields and conjugate momenta. The leading hard mode contribution is incorporated in the equations of motion for the classical fields. This yields the gauge invariant hard thermal loop (HTL) effective equation of motion. No gauge-variant terms are generated as in treatments with an intermediate momentum cut-off. Quantum corrections to classical correlation functions can be calculated perturbatively. The 4D renormalizability of the theory ensures that the 4D counterterms are sufficient to render the theory finite. The HTL contributions of the quantum fluctuations provide the counterterms for the linear divergences in the classical theory.

hep-ph↗

arXiv1997

Real-time contour propagator for high temperature dimensional reduction

We discuss the extension of dimensional reduction in thermal field theory at high temperature to real-time correlation functions. It is shown that the perturbative corrections to the leading classical behavior of a scalar bosonic field theory are determined by an effective contour propagator. On the real-time-branch of the time-path contour the effective propagator is obtained by subtracting the classical propagator from the contour propagator of thermal field theory, whereas on the Euclidean branch it reduces to the non-static Matsubara propagator of standard dimensional reduction.

hep-ph↗