Speaker: Harshit Pandey (Institute of Mathematical Sciences, Chennai)
Title of Talk: Understanding the approach to thermalization in a non-Abelian gauge theory
Abstract: In this talk, I will discuss how we can understand the process of thermalization in a strongly interacting quantum field theory, QCD, in terms of the soft momentum modes of gauge fields. We use ab-initio lattice techniques for this work. Studying the properties of eigenvalues of the QCD Dirac operator, we show that these soft modes in a high temperature non-Abelian plasma are chaotic, following level-spacing ratios similar to random matrices belonging to a Gaussian unitary ensemble. Furthermore, the maximal Lyapunov exponent $\lambda_L$ of physical states in a non-Abelian gauge theory consisting of soft momentum modes both in- and out-of-thermal equilibrium conditions is positive definite, further re-inforcing its chaotic nature. From the Kolmogorov-Sinai entropy rate measured in terms of this spectrum of positive $\lambda_L$, we estimate a typical time-scale of $\sim 0.50(3)$ fm/c to achieve thermalization at $T\sim 600$ MeV starting from a particular non-thermal state consisting of over-occupied gluons, believed to exist in the early stages of a heavy-ion collision event .
Venue: Goldene Box in Physikalisches Institut, INF 226 (ground floor)
Schedule:
Talk: 16:30 – 17:15
Questions & Discussion: 17:15 – 17:30
Pizza & Drinks: 17:30
_____________________________________________________________________________________________