2007/08/31 by Aleksey Cherman, Thomas D. Cohen, Paul M. Hohler · 5 citations
Mathematics · Physics and Astronomy · #Black Holes and Theoretical Physics #Combinatorics #Conjecture #Counterexample #Entropy (arrow of time) #Geometric Analysis and Curvature Flows #Mathematical analysis #Mathematics #Nonlinear Partial Differential Equations #Physics #Shear viscosity #Statistical physics #Thermodynamics #Upper and lower bounds #Viscosity #cond-mat.stat-mech #hep-ph #hep-th #nucl-th #physics.flu-dyn
paper · pdf · doi:10.1088/1126-6708/2008/02/026
published as JHEP 0802:026,2008 · 23 pages, 4 figures, added references, corrected typos, added subsection in response to Son's comments in arXiv:0709.4651
arxiv created 2007/12/03 · openalex publication_date 2008/02/12 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
There have been a number of forms of a conjecture that there is a universal lower bound on the ratio, eta/s, of the shear viscosity, eta, to entropy density, s, with several different domains of validity. We examine the various forms of the conjecture. We argue that a number of variants of the conjecture are not viable due to the existence of theoretically consistent counterexamples. We also note that much of the evidence in favor of a bound does not apply to the variants which have not yet been ruled out.