Abstract:
It is usually believed that physics in off-equilibrium state characterized by hydrodynamic gradient can be equivalently studied using equilibrium state with suitable metric perturbation. We scrutinize this assumption using chiral kinetic theory in curved space, focusing on spin response to hydrodynamic gradient. Two effects of metric perturbation have been identified: one is the change of particle motion, which allows for description of spin response to vorticity only. The other is the genuine effect of off-equilibrium state, which is realizable by mapping the equilibrium state in curved space to flat space through a suitable frame choice. It allows for study of spin response to more general hydrodynamic gradient. We classify off-equilibrium effect on spin polarization into modifications of (i) spectral function; (ii)distribution function; and (iii) KMS relation. While the last two have been studied using chiral kinetic theory, the first one is usually ignored in kinetic description. We perform a detailed analysis on the first one, finding the radiative correction to spectral function leads to a polarized quasi-particle. The degeneracy of spin responses to different hydrodynamic sources at tree-level is also lifted byradiative correction
Biography:
Shu Lin received his B.S. from Peking University in 2004 and Ph.D. from Stony Brook University in 2010. He served as a postdoctoral researcher at Max Planck Institute for Physics in Munich (2010-2012) and Brookhaven National Laboratory (2012-2015). He joined Sun Yat-sen University in 2015. He is currently a Professor at Sun Yat-sen University. His research interest includes spin phenomenon in heavy ion collisions and field theory at finite temperature.
Host: Prof. Yifeng Sun
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