English

Phase Transitions and the Perfectness of Fluids

High Energy Physics - Phenomenology 2009-01-01 v4 Other Condensed Matter Soft Condensed Matter High Energy Physics - Lattice Nuclear Experiment Nuclear Theory

Abstract

We calculate the ratio eta/s, the shear viscosity (eta) to entropy density (s), which characterizes how perfect a fluid is, in weakly coupled real scalar field theories with different types of phase transitions. The mean-field results of the eta/s behaviors agree with the empirical observations in atomic and molecular systems such as water, He, N, and all the matters with data available in the NIST database. These behaviors are expected to be the same in N component scalar theories with an O(N) symmetry. We speculate these eta/s behaviors are general properties of fluid shared by QCD and cold atoms. Finally, we clarify some issues regarding counterexamples of the conjectured universal eta/s bound found in Refs.[16,17].

Keywords

Cite

@article{arxiv.0709.3434,
  title  = {Phase Transitions and the Perfectness of Fluids},
  author = {Jiunn-Wei Chen and Mei Huang and Yen-Han Li and Eiji Nakano and Di-Lun Yang},
  journal= {arXiv preprint arXiv:0709.3434},
  year   = {2009}
}

Comments

5 pages, 2 figures; Fig. 2 changed; journal version

R2 v1 2026-06-21T09:20:07.731Z