ausblenden:
Schlagwörter:
High Energy Physics - Theory, hep-th,General Relativity and Quantum Cosmology, gr-qc,High Energy Physics - Phenomenology, hep-ph
Zusammenfassung:
We holographically study the far-from-equilibrium isotropization dynamics of
the strongly coupled $\mathcal{N}=4$ supersymmetric Yang-Mills plasma. The dual
gravitational background is driven to be out of equilibrium and anisotropic by
a time-dependent change in boundary conditions. At late times, the system
relaxes and asymptotically approaches a static configuration. The large initial
energy densities accelerate the isotropization significantly compared to the
initial geometry corresponding to the supersymmetric Yang-Mills vacuum. We
analyze shear transport during isotropization by directly computing the
time-dependent stress tensor, which is now a nonlinear function of the shear
rate. The shear viscosity far from equilibrium displays much richer dynamics
than its near-equilibrium counterpart. Moreover, we uncover that the
equilibrium viscosity-to-entropy ratio at late times depends on the details of
the quench function and the initial data, which could be due to a resummation
of the hydrodynamic description. In particular, this ratio can be
parametrically smaller than the Kovtun-Son-Starinets bound calculated from
linear response theory.
