Evolving Glasma and Kolmogorov Spectrum

TL;DR

This paper explores the evolution of the Glasma in heavy-ion collisions, demonstrating how instabilities and turbulence lead to a Kolmogorov spectrum consistent with -5/3 scaling.

Contribution

It introduces the development of Glasma instabilities and turbulence, connecting classical field evolution with Kolmogorov scaling in a heavy-ion collision context.

Findings

Glasma instability enhances rapidity-dependent fluctuations.

Turbulent energy flow leads to a power-law spectrum.

Numerical results match Kolmogorov's -5/3 scaling.

Abstract

We present a pedagogical introduction to the theoretical framework of the Color Glass Condensate (CGC) and the McLerran-Venugopalan (MV) model. We discuss the application of the MV model to describe the early-time dynamics of the relativistic heavy-ion collision. Without longitudinal fluctuations the classical time evolution maintains the boost invariance, while an instability develops once fluctuations that break boost invariance are included. We show that this "Glasma instability" enhances rapidity-dependent variations as long as self-interactions among unstable modes stay weak and the system resides in the linear regime. Eventually the amplitude of unstable modes becomes so large that the growth of instability gets saturated. In this non-linear regime the numerical simulations of the Glasma lead to turbulent energy flow from low-frequency modes to higher-frequency modes, which results in a characteristic power-law spectrum. The power found in numerical simulation of the expanding Glasma system turns out to be consistent with Kolmogorov's -5/3 scaling.