Quantum corrections to η/s from JT gravity

A

bstract

We revisit the computation of the shear viscosity to entropy ratio η / s at finite chemical potential in a holographic model that takes into account the quantum fluctuations in the IR region of near-extremal black branes. Such quantum corrections can be computed from JT gravity and generate non-trivial temperature dependence for η / s , which deviates from the universal 1/4 π result. In the semi-classical regime, η / s attains a minimum which is below the KSS bound, generated by the presence of the quantum effects. In the quantum regime at lower temperatures, η / s increases and is well above the KSS bound. We also compare the shear viscosity to the quantum-corrected absorption cross-section of near-extremal black holes, and find agreement.