Power spectrum of flow fluctuations in relativistic heavy-ion collisions

TL;DR

This paper uses hydrodynamical simulations to analyze the power spectrum of flow fluctuations in relativistic heavy-ion collisions, revealing strong parallels with cosmic microwave anisotropies and identifying key fluctuation suppression effects.

Contribution

It demonstrates the correspondence between flow fluctuation spectra in heavy-ion collisions and cosmic microwave anisotropies, highlighting the suppression of superhorizon fluctuations and linking the first peak to the freezeout scale.

Findings

Strong correlation between flow fluctuation power spectrum and cosmic microwave anisotropies

Suppression of superhorizon fluctuations observed

First peak in spectrum related to freezeout scale

Abstract

We carry out hydrodynamical simulation of the evolution of fluid in relativistic heavy-ion collisions with random initial fluctuations. The time evolution of power spectrum of momentum anisotropies shows very strong correspondence with the physics of cosmic microwave anisotropies as was earlier predicted by some of us. In particular our results demonstrate suppression of superhorizon fluctuations and the correspondence between the location of the first peak in the power spectrum of momentum anisotropies and the length scale of fluctuations and expected freezeout time scale (more precisely, the sound horizon size at freezeout).