Year: 2019
Type: article
Abstract: A quantitatively reliable theoretical description of the dynamics of fluctuations in nonequilibrium is indispensable in the experimental search for the QCD critical point by means of ultrarelativistic heavy-ion collisions. In this paper we consider the fluctuations of the net-baryon density which becomes the slow, critical mode near the critical point. Due to net-baryon number conservation the dynamics is described by the fluid dynamical diffusion equation, which we extend to contain a white noise stochastic current. Including nonlinear couplings from the 3d Ising model universality class in the free energy functional, we solve the fully interacting theory in a finite size system. We observe that purely Gaussian white noise generates non-Gaussian fluctuations, but finite size effects and exact net-baryon number conservation lead to significant deviations from the expected behavior in equilibrated systems. In particular the skewness shows a qualitative deviation from infinite volume expectations. With this benchmark established we study the real-time dynamics of the fluctuations. We recover the expected dynamical scaling behavior and observe retardation effects and the impact of critical slowing down near the pseudocritical temperature.
Institutions: Centre National de la Recherche Scientifique, GSI Helmholtz Centre for Heavy Ion Research, Laboratoire de Physique Subatomique et des Technologies Associées, IMT Atlantique, Institut National de Physique Nucléaire et de Physique des Particules, Université de Nantes, ExtreMe Matter Institute EMMI, Nantes Université, University of Wrocław, North Carolina State University, Duke University
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: QCD, HADRONS AND DENSE MATTER, G222768804, NUCLEAR THEORY AT NORTH CAROLINA STATE UNIVERSITY, SUPPORTING MOBILITY IN THE ERA THROUGH AN INTERNATIONAL FELLOWSHIP PROGRAMME FOR DEVELOPEMENT OF BASIC RESEARCH IN POLAND, NUCLEAR PHYSICS AT EXTREME ENERGY DENSITY, NUCLEAR PHYSICS AT HIGH ENERGY DENSITY
OpenAlex ID: W2796748938