Spectral function for overoccupied gluodynamics from real-time lattice simulations

Abstract

We study the spectral properties of a highly occupied non-Abelian nonequilibrium plasma appearing ubiquitously in weak coupling descriptions of QCD matter. The spectral function of this far-fromequilibrium plasma is measured by employing linear response theory in classical-statistical real-time lattice Yang-Mills simulations. We establish the existence of transversely and longitudinally polarized quasiparticles and obtain their dispersion relations, effective mass, plasmon frequency, damping rate and further structures in the spectral and statistical functions. Our new method can be interpreted as a nonperturbative generalization of hard thermal loop (HTL) effective theory. We see indications that our results approach leading order HTL in the appropriate limit. The method can also be employed beyond the range of validity of HTL.

Highly occupied gauge theories in 2+1 dimensions: A self-similar attractor

“…The longitudinally polarized correlator E L E * L approaches E T E * T at the lowest momenta, while strongly differing for momenta above the Debye mass m D . Indeed, as known in thermal equilibrium [5] and also observed far from equilibrium in the 3D theory [36], the longitudinal correlation function follows the form…”

“…To learn more about soft dynamics, further numerical studies are required. These include also unequal-time correlators that can be studied numerically with methods that have been developed recently [41] and successfully used for 3-dimensional systems [36,42]. We will report on results from such studies in a subsequent work.…”

“…A description of this standard technique can be found, for instance, in Refs. [9,36]. Then all fields are classical and discretized on a cubic lattice of size N 2 s with lattice spacing a s .…”

Many-body chaos near a thermal phase transition

“…Moreover, it can be used to evaluate the spectral function in regimes in which the FDR does not hold, such as for out-of-equilibrium initial states, as it is related to the numerical linear response theory introduced in Ref. [48,49].…”

Spectral Function for Overoccupied Gluodynamics from Classical Lattice Simulations

“…This talk reviews the recent results presented in more detail in Ref. [7]. In the following we shall briefly describe our numerical method of linearized fluctuations, based on the algorithm developed in Ref.…”