Chiral Superfluidity for the Heavy Ion Collisions

TL;DR

This paper models the quark-gluon plasma as a chiral superfluid, revealing new effects like the chiral magnetic and electric phenomena through hydrodynamic analysis, and suggests experimental tests for this two-component fluid model.

Contribution

It introduces a novel two-component model of the quark-gluon plasma as a chiral superfluid using bosonization and hydrodynamics, predicting specific electromagnetic effects.

Findings

Chiral magnetic and electric effects arise in the model.

Spectral analysis supports the two-component structure.

Experimental tests can distinguish this model from others.

Abstract

We argue that the strongly coupled quark-gluon plasma formed at LHC and RHIC can be considered as a chiral superfluid. The "normal" component of the fluid is the thermalized matter in common sense, while the "superfluid" part consists of long wavelength (chiral) fermionic states moving independently. We use the bosonization procedure with a finite cut-off and obtain a dynamical axion-like field out of the chiral fermionic modes. Then we use relativistic hydrodynamics for macroscopic description of the effective theory obtained after the bosonization. Finally, solving the hydrodynamic equations in gradient expansion, we find that in the presence of external electromagnetic fields the motion of the "superfluid" component gives rise to the chiral magnetic, chiral electric and dipole wave effects. Latter two effects are specific for a two-component fluid, which provides us with crucial experimental tests of the model. By considering probe quarks one can show that the fermionic spectrum at the intermediate temperatures (T_c < T < 2 T_c) has a gap between near-zero modes and the bulk of the spectrum - one more hint supporting the two-component model.