Spinodal amplification of density fluctuations in fluid-dynamical simulations of relativistic nuclear collisions

TL;DR

This paper uses fluid-dynamical simulations of relativistic nuclear collisions to study how density fluctuations are amplified in the spinodal region, potentially signaling a phase transition through increased composite particle production.

Contribution

It extends a two-phase equation of state with a finite-range term to simulate and analyze density fluctuation amplification during relativistic nuclear collisions.

Findings

Density irregularities are significantly amplified in the spinodal region.

Density clumping could serve as a signal of the phase transition.

Enhanced production of composite particles may indicate spinodal amplification.

Abstract

Extending a previously developed two-phase equation of state, we simulate head-on relativistic lead-lead collisions with fluid dynamics, augmented with a finite-range term, and study the effects of the phase structure on the evolution of the baryon density. For collision energies that bring the bulk of the system into the mechanically unstable spinodal region of the phase diagram, the density irregularities are being amplified significantly. The resulting density clumping may be exploited as a signal of the phase transition, possibly through an enhanced production of composite particles.