# Quark Matter 2018

13-19 May 2018
Venice, Italy
Europe/Zurich timezone
The organisers warmly thank all participants for such a lively QM2018! See you in China in 2019!

## Causal Charge Diffusion and Fluctuations in Heavy-Ion Collisions

15 May 2018, 17:00
2h 40m
First floor and third floor (Palazzo del Casinò)

### First floor and third floor

#### Palazzo del Casinò

Poster Correlations and fluctuations

### Speaker

Christopher Plumberg

### Description

We present a relativistic causal description of conserved-charge diffusion for heavy-ion collisions and show that it produces measurable effects in observables such as the charge balance functions. Other descriptions, based on ordinary diffusion, are known to produce charge fluctuations which propagate with infinite velocity, thus violating a fundamental postulate of special relativity. We present an alternative approach based on Cattaneo diffusion which restores relativistic causality, and show how to generalize this approach to dynamical, rapidly evolving systems such as heavy-ion collisions. We demonstrate that this approach leads to measurable consequences for the balance functions constructed from electrically charged hadrons in a simple 1+1 dimensional Bjorken hydrodynamic model. We find that limiting the speed of propagation of charge fluctuations increases the height and reduces the width of these balance functions when plotted versus separation in rapidity. We conclude by estimating the numerical value of the associated diffusion time constant from AdS/CFT.

Content type Theory Presenter name already specified

### Primary author

Joseph Kapusta (University of Minnesota)