holographic description of shear viscosity to entropy ratio

Strongly coupled field theory can be described by calculation of η/s from fluid-gravity duality since this value is proportional to the inverse square coupling of field theory. this ratio should be larger than η/s≥1/4π, and it is known as a conjecture in the literature. we calculate the ratio of shear viscosity per entropy density for a dilaton black brane in ads spacetime. our result shows that this bound is saturated in this black brane and the field theory dual of our model is the same as field theory dual einstein gravity.