Retarded correlators in kinetic theory: branch cuts, poles and hydrodynamic onset transitions

The European Physical Journal C

Paul Romatschke¹ 

[1] Department of Physics, University of Colorado, 80309, Boulder, CO, USA;Center for Theory of Quantum Matter, University of Colorado, 80309, Boulder, CO, USA;

关键词: Gauge Theory;    Kinetic Theory;    Hooft Coupling;    Hydrodynamic Limit;    Onset Transition;   

DOI  :  10.1140/epjc/s10052-016-4169-7

来源: Springer

【 摘 要 】

In this work the collective modes of an effective kinetic theory description based on the Boltzmann equation in a relaxation-time approximation applicable to gauge theories at weak but finite coupling and low frequencies are studied. Real time retarded two-point correlators of the energy-momentum tensor and the R-charge current are calculated at finite temperature in flat space-times for large N gauge theories. It is found that the real-time correlators possess logarithmic branch cuts which in the limit of large coupling disappear and give rise to non-hydrodynamic poles that are reminiscent of quasi-normal modes in black holes. In addition to branch cuts, correlators can have simple hydrodynamic poles, generalizing the concept of hydrodynamic modes to intermediate wavelength. Surprisingly, the hydrodynamic poles cease to exist for some critical value of the wavelength and coupling reminiscent of the properties of onset transitions.

【 授权许可】

CC BY