Blackhole substances are perhaps the most-perfect fluids in existence because they have ultra-low viscosity.
Son and two colleagues used a string theory method called the gauge/gravity duality to determine that a black hole in 10 dimensions - or the holographic image of a black hole, a quark-gluon plasma, in three spatial dimensions - behaves as if it has a viscosity near zero, the lowest yet measured.
***2. A quark-gluon plasma, with the same quarks, but with "bags" disappeared and gluons flying around in their place. See: Just in case anyone forgot...
One of the things I worked a lot on in earlier months this year (and late ones of last year) was the lead article in a cluster of articles that has appeared in the last few days in May’s special edition of Physics Today. They are sort of departmental-colloquium-level articles, so for a general physics audience, more or less. It’s about some of the things I’ve told you about here in the past (see e.g. here and here), concerning exciting and interesting applications of string theory to various experiments in nuclear physics, as well as atomic and condensed matter physics (although we do not have an article on the latter in this cluster). I had a fun time working with Peter Steinberg on the article and remain grateful to him for getting us all together in the first place to talk about this topic way back in that AAAS symposium of 2009. It was there that Steven Blau of Physics Today got the excellent idea to approach us all to do an article, which resulted in this special issue....See: The Search For Perfection…
Clifford gives a link to the PDF version of the online article "What black holes teach about strongly coupled particles" I am not sure the article is free anymore as it now requires registry. Clifford has adjusted to this by giving "his" pdf link.
Cover: In contrast with everyday liquids such as the oil and water shown on the cover, a so-called perfect fluid has exceedingly low shear viscosity. But unlike a superfluid, the perfect fluid is not in a single quantum state. Three articles in this issue explore the connection to string theory (beginning on page 29) and the possible existence of perfect fluids in two very different regimes: ultracold fermionic atoms (page 34) and ultrahot nuclear matter (page 39). (Photo by Stefan Kaben.)
Physics Bits and Bites
The quest for Quantum Ideal liquids