High-Temperature Effective Potential of Noncommutative Scalar Field Theory: Reduction of Degree of Freedom by Noncommutativity

TL;DR

This paper investigates the high-temperature effective potential in noncommutative scalar field theory, revealing that nonplanar diagrams, influenced by noncommutativity, have a reduced impact on symmetry restoration due to a decrease in degrees of freedom.

Contribution

It demonstrates that nonplanar two-loop diagrams can be neglected at high temperatures, highlighting the reduction of degrees of freedom caused by noncommutativity.

Findings

Nonplanar diagrams do not restore symmetry breaking at high temperature.

Nonplanar contributions are negligible compared to planar diagrams.

Noncommutativity reduces degrees of freedom in nonplanar diagrams.

Abstract

The renormalization of effective potentials for the noncommutative scalar field theory at high temperature are investigated to the two-loop approximation. The Feynman diagrams in evaluating the effective potential may be classified into two types: the planar diagrams and nonplanar diagrams. The nonplanar diagrams, which depend on the parameter of noncommutativity, do not appear in the one-loop potential. Despite their appearance in the two-loop level, they do not have an inclination to restore the symmetry breaking in the tree level, in contrast to the planar diagrams. This phenomenon is explained as a consequence of the drastic reduction of the degrees of freedom in the nonplanar diagrams when the thermal wavelength is smaller than the noncommutativity scale. Our results show that the nonplanar two-loop contribution to the effective potential can be neglected in comparsion with that from the planar diagrams.