Expanding color flux tubes and instabilities

TL;DR

This paper analytically studies the early-stage glasma in high-energy heavy-ion collisions, revealing flux tube expansion, decay of field strength, and magnetic instabilities, with implications for understanding quark-gluon plasma formation.

Contribution

It provides a novel analytic analysis of flux tube dynamics and instabilities in the glasma, highlighting magnetic instabilities and the decay process of color fields.

Findings

Magnetic flux tubes exhibit instabilities due to Landau level fluctuations.

Electric flux tubes decay rapidly without apparent instabilities.

Magnetic instabilities grow on the order of 1/Q_s, influencing early glasma evolution.

Abstract

We present an analytic study of the physics of the glasma which is a strong classical gluon field created at early stage of high-energy heavy-ion collisions. Our analysis is based on the picture that the glasma just after the collision is made of color electric and magnetic flux tubes extending in the longitudinal direction with their diameters of the order of 1/Q_s (Q_s is the saturation scale of the colliding nuclei). We find that both the electric and magnetic flux tubes expand outwards and the field strength inside the flux tube decays rapidly in time. Next we investigate whether there exist instabilities against small rapidity-dependent perturbations for a fixed color configuration. We find that the magnetic background field exhibits an instability induced by the fluctuations in the lowest Landau level, and it grows in the time scale of 1/Q_s. For the electric background field we find no apparent instability while the possible relation to the Schwinger mechanism for particle pair creations is suggested.