Influence of a Critical Point on Hydrodynamic Fluctuations in Heavy Ion Collisions

TL;DR

This paper models how hydrodynamic fluctuations in heavy ion collisions are amplified near a critical point, using a diverging thermal conductivity to predict observable proton correlations.

Contribution

It introduces a model for thermal conductivity diverging at the critical point and demonstrates its impact on proton correlations in heavy ion collision simulations.

Findings

Proton correlation functions are sensitive to the critical point.

Thermal conductivity diverges with correct critical exponents near the critical point.

Fluctuations are significantly enhanced when the trajectory passes close to the critical point.

Abstract

Hydrodynamic fluctuations have been studied in a wide variety of physical, chemical, and biological phenomena in the past decade. In high energy heavy ion collisions, there will be intrinsic fluctuations even if the initial conditions are fixed. Fluctuations will be greatly enhanced if the trajectory in the plane of temperature versus chemical potential passes near a critical point. We construct a model for the thermal conductivity which diverges at the critical point with the correct critical exponents, and use it in a simple illustrative model of a heavy ion collision. The proton correlation function is sensitive to the presence of the critical point.