Basic theory and some applications concerning the ratio of shear viscosity to entropy density in dense fluids

Abstract

Much interest continues relating to the conjecture from string theory of an inequality satisfied by the ratio η/s in dense fluids, where η is the shear viscosity and s the entropy density. First, we summarise the models which have prompted the proposal of the inequality. Second, we consider a model equation of state which may be appropriate for the dense fluids NH₃ and H₂O, both of which satisfy the inequality.

Keywords:

• dense fluids
• equation of state
• string theory

Acknowledgements

The authors wish to acknowledge that this Letter was initiated during a stay at the Department of Physics, University of Antwerp (UA), Belgium. Thanks are due to Professors C. Van Alsenoy and D. Lamoen for their warm hospitality. N.H. March was partially supported by UA through the BOF-NOI.