Archive for May, 2009
The coming collapse of the middle class
As usual on Saturdays, discussion of physics is forbidden (why? check out Old Testament). Let us talk a bit about global financial crisis instead , namely about work of Elizabeth Warren, professor of Harvard Law School. Elizabeth Warren was a senior consultant of Clinton’s National Bankruptcy Review Commission – the one which tried to figure [...]
Workshop on tests of gravity in Case Western – day 2: aether and modified gravity
Let me finally briefly review the reminder of the second day of the workshop. Justin Khoury (whom I knew from Perimeter years and who is in Penn now) gave the first talk afternoon – titled “observational hints of IR modified gravity”. His talk followed Nima’s, and the latter almost completely blew me away, so I [...]
Susskind’s general relativity – lecture 9
… where Leonard Susskind discusses spacetime – spacelike, timelike and lightlike directions, explains how one gets special relativity from general relativity (post-Newtonian approximation), non-relativistic limit of GR and finally … Einstein equations (hurray!)
Workshop on tests of gravity in Case Western – day 2 and Arkani-Hamed’s talk
The second day of the Workshop on Tests of Gravity (and here is my blog post about the first day) was mostly devoted to analog models (Bill Unruh, Michael Uhlmann, George Pickett) and models of modified gravity (Nima Arkani-Hamed, Justin Khoury, Stacy McGaugh, Ted Jacobson, Levon Pogosyan and Mark Wyman). Regarding analog models I don’t [...]
Susskind’s 8th lecture on general relativity
Leonard Susskind continues reading his lecture course on general relativity in U. of Stanford. Previous lectures can be found here: Lectures 1-5, Lecture 6 and Lecture 7. Susskind continues to discuss covariant derivatives, parallel transport of vectors, Ricci and Riemann tensors. In the second part of the lecture he turns to geodesics. He is terrific [...]
Workshop on tests of gravity at Case Western – day 1
Dear friends, I am sorry for being rather quiet for a while. As many of you may already know, my laptop has decided to enter coma during the trip, as a result, I was left without appropriate internet access (sporadic use of Pascal Vaudrevange’s computer is not counted, thanks, Pascal!). Although the laptop tried to [...]
Things that go bump in the CMB polarization
This post is written by Michael Mortonson, graduate student of Wayne Hu at the U. of Chicago. Michael has also asked me to thank Cora Dvorkin and Wayne Hu (U. of Chicago), and Hiranya Peiris (U. of Cambridge), who contributed to the post. Dmitry. One of the most impressive results from experiments that have measured [...]
Real-time gauge/gravity duality
Balt van Rees from the U. of Amsterdam continues the discussion of non-equilibrium AdS/CFT we have started not so long time ago. Since his recent paper with Skenderis was one of the major achievements in the field, I highly recommend going through his post. Dmitry. Our recent paper Real-time gauge/gravity duality offers a prescription for [...]
Correlator of Wilson and t’Hooft loops at strong coupling in N=4 SYM theory
Andrew Zayakin works at LMU, Munich and ITEP, Moscow. His interests include non-perturbative physics of QCD, string theory and AdS/CFT correspondence. Dmitry. This post is about my recent paper with Alexander Gorsky and Alexander Monin about a correlator of a Wilson and a ‘t Hooft loop. Before I proceed, I should explain what these objects [...]
String theory and the diffusion equation
Gianluca Calcagni is a postdoc at Penn State working in the group of Martin Bojowald. His interests include string theory, string field theory and cosmology. Dmitry. This post is based on arXiv:0904.3744, in collaboration with Giuseppe Nardelli. Check the links for references and introductory reviews on the subject. A question. The prototype of instanton in [...]