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In
certain systems, complex far-from-equilibrium dynamics in a wide range
of time evolution trajectories quickly lose memory of their initial
conditions and make way to universal phenomena that simplify the
system's state. A prominent example is the hydrodynamic attractor,
which appears in the Bjorken flow model of early time dynamics in
heavy ion collisions. In this talk, I will first briefly review what
is known about the hydrodynamic attractor in Bjorken flow and then
discuss how expectations from this simple case are broken in two newly
discovered examples of attractors.
The
attractor in ultracold atomic gases is a promising avenue for a direct
experimental detection of attractor behaviour. It is in many ways
distinct from the heavy ion case, proving that the phenomenon extends
to many more systems than the original formulation may indicate.
However, in strongly driven systems heating will obscure a collapse
onto a universal curve in single observables. The behaviour must
instead be diagnosed via a method that considers dimensional reduction
in the full state space.
The
earliest times of heavy ion collision features high gluon occupations,
which may be described as classical fields. This motivates a study of
hydrodynamic attractor behaviour in classical Yang-Mills theory with
Bjorken-like symmetries. A major difference to other dynamical
descriptions in which the behaviour has been diagnosed is the fact
that this theory does not hydrodynamize. Indeed, it features only
expansion driven, but no interaction driven memory loss. Even more
strikingly, some of the lost memory is recovered again while expansion
still dominates the dynamics.
The talk will be live-streamed (but not recorded) via Zoom under
https://uni-frankfurt.zoom.us/j/2848286010?pwd=VmtCY1RCc1hpVStKd0RibFBpc1IzZz09
Transport and
Magnetohydrodynamics Meeting