Off-equilibrium non-Gaussian fluctuations near the QCD critical point: an effective field theory perspective

Abstract

The non-Gaussian fluctuations of baryon density are sensitive to the presence of the conjectured QCD critical point. Their observational consequences are crucial for the ongoing experimental search for this critical point through the beam energy scan program at Relativistic Heavy Ion Collider (RHIC). In the expanding fireball created in a heavy-ion collision, critical fluctuations would inescapably fall out of equilibrium, and require a systematic description within a dynamical framework. In this paper, we employ newly developed effective field theory (EFT) for fluctuating hydrodynamics to study the real-time critical non-Gaussian fluctuations of a conserved charge density. In particular, we derive the evolution equations for multi-point correlators of density fluctuations and obtain the closed-form solutions with arbitrary initial conditions that can readily be implemented in realistic simulations for heavy-ion collisions. We find that non-linear interactions among noise fields, which are missing in traditional stochastic hydrodynamics, could potentially contribute to the quartic (fourth order) fluctuations in scaling regime even at tree level in off-equilibrium situations.

arXiv comment25 pages

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Cited by in corpus (8)

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• Dynamics of non-Gaussian fluctuations in model A
• Corrections to diffusion in interacting quantum systems
• Holographic Schwinger-Keldysh field theory of SU(2) diffusion
• Long-time tails in the SYK chain from the effective field theory with a large number of derivatives
• Rapidity scan approach for net-baryon cumulants with a statistical thermal model
• N-particle irreducible actions for stochastic fluids
• Conservation Laws and Hydrodynamics