Finite size effects on the phase diagram and the baryon fluctuations via momentum space constraints

TL;DR

This study investigates how finite system size and momentum space constraints influence the QCD phase diagram and baryon fluctuations, revealing significant shifts in critical points and fluctuations for systems smaller than about 10 fm.

Contribution

It systematically analyzes the impact of different momentum space constraints and boundary conditions on the finite size effects in the QCD phase diagram using a mean-field quark-meson model.

Findings

Critical endpoint location shifts significantly for system sizes below 10 fm.

Momentum space constraints strongly influence volume dependence of phase transitions.

Baryon fluctuations are affected by finite size effects along the phase boundary.

Abstract

The effect of the finite system size on the QCD phase diagram was studied with various momentum space constraints within a mean-field quark-meson model. On the one hand side, the choice of the scenario -- low-momentum cutoff and discretization with periodic or antiperiodic boundary conditions -- and the presence of the vacuum fluctuations were found to strongly affect the volume dependence of the CEP. On the other hand, its location is significantly shifted in each case for linear sizes below $L\approx 10$ fm. This is also reflected in the conserved charge fluctuations, which were investigated along the phase boundary using multiple scenarios for the finite size effects.