Currently at the KITP

Right now I’m in the midst of a program I helped to organize (and I’m still organizing) at the KITP. The program deals with the question of how to use numerical methods from lattice and gravity to make inroads into interesting (usually very hard) questions about quantum field theory (and quantum gravity) and the dynamics [...]

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Novel Numerical Methods for Strongly Coupled Quantum Field Theory and Quantum Gravity

Here is an announcement of a program I will be organizing at the KITP from Jan 17 thru March 9 2012. It is a program on numerical methods for gravity and QFT. The web page of the program is located here. Here is the image I made to illustrate the program: it is generated by [...]

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Cosmic censorship in five dimensions

New evidence against cosmic censorship in five dimensions was announced today in the arxiv. The evidence is numerical, but it is done by a very good group of people working on numerical general relativity: Luis Lehner and Frans Pretorius. They argue that in the black string Gregory Laflamme instability the system develops `singularities in finite [...]

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Must read papers of the week

The Gravity Research Foundation announced the results of the 2010 competition. Here are the results. At UCSB we discussed the prize-winning paper by Mark van Raamsdonk today. It was a very lively discussion and we thought it was a great paper to read. Mark’s paper provided some very tantalyzing evidence that entanglement seems to play [...]

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Black holes as frozen stars

We now have a few working examples of a microscopic theory of quantum gravity, all come with specific boundary conditions (like any other equation in physics or mathematics), but otherwise full background independence. In particular, all those theories include quantum black holes, and we can ask all kinds of puzzling questions about those fascinating objects. [...]

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Where is the gauge theory?

Comments by Giotis on my previous post, about emergent gravity, reminded me about one of the tricky points in gauge-gravity dualities such as the AdS/CFT correspondence. This is the understanding of them as dualities between one theory that lives in the “bulk” spacetime (say quantum gravity on five dimensional AdS space) and another that lives [...]

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Emergent gravity

Alright, time to discuss some physics again. A while back I outlined the basic dichotomy of quantum gravity. In brief: we have classical general relativity as an excellent description of all observed gravitational phenomena, but when we go to extremely short distances we need to have a good description of quantum gravity. There are two [...]

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The universal law of gravitation

So I have been pondering about Newton lately. Mostly because I heard various stories that might be apocryphal. I could not find a reference to them, but they strike me as being true. There is a legend about apples falling on Isaac Newton’s head as a story of how he discovered the law of gravitation… [...]

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