The Effect of Fluctuations on the QCD Critical Point in a Finite Volume

TL;DR

This paper studies how finite volume effects influence the position of the QCD critical point using a quark-meson model, highlighting the importance of fluctuations and boundary conditions in shifting the critical point.

Contribution

It introduces a renormalization group approach to analyze finite volume effects on the QCD critical point, incorporating fluctuations absent in mean-field models.

Findings

Critical point shifts to lower temperatures with decreasing volume.

Quantum and thermal fluctuations significantly affect the critical behavior.

Boundary conditions have a notable impact on the critical point location.

Abstract

We investigate the effect of a finite volume on the critical behavior of the theory of the strong interaction (QCD) by means of a quark-meson model for two quark flavors. In particular, we analyze the effect of a finite volume on the location of the critical point in the phase diagram existing in our model. In our analysis, we take into account the effect of long-range fluctuations with the aid of renormalization group techniques. We find that these quantum and thermal fluctuations, absent in mean-field studies, play an import role for the dynamics in a finite volume. We show that the critical point is shifted towards smaller temperatures and larger values of the quark chemical potential if the volume size is decreased. This behavior persists for antiperiodic as well as periodic boundary conditions for the quark fields as used in many lattice QCD simulations.