EDIT ADDED: This page is outdated.

Most of this is technical stuff related to strings, cosmology, etc., and its not even up to date. Links to my pages on non-physics things are at the bottom.

An introductory lecture on string theory. First, I try to motivate why quantizing gravity is hard. This part of the lecture will need you to be familiar with some ideas of quantum field theory and general relativity, but if you are willing to believe that string theory IS necessary, you can start with the later sections which give a fairly self-contained introduction to the subject.

Here is an old article on d-branes that I did with Marija. D-branes are membrane-like dynamical objects in string theory, and they are interesting because among other things, our universe could be a four-dimensional membrane living in a higher dimensional spacetime. That, it turns out, would explain why gravity is so weak compared to the other forces: gravity can leak off into the bulk-spacetime, but the other forces can't. (You need ghostview to see this postscript file!!)

Here is an article on the Gukov-Vafa conjecture that connects rationality of CFTs on Calabi-Yau manifolds to certain number theoretic properties of the manifold. On page 10, I say that "for any CY manifold, one can construct a mirror", when what I mean is actually only that the mirror exists - constructing them is not always the easiest proposition. (You need ghostview to see this!!)

Mathematical take on Anomalies. Anomalies are inconsistencies in the mathematical description of a quantum field theory. Some can be rectfified, some cannot. Here, I focus on the algebraic, topological and cohomological aspects of anomalies. Don't expect to see a path-integral calculation of the ABJ axial vector non-conservation. (You need ghostview to see this!!)

A paper with Sonia and Marija on stability of de-Sitter type universes. (And you do NOT need ghostview to see this!!)

A paper with Edoardo on the construction of a multi-parametric Drinfeld Jimbo algebra for so(4,1). (And you do NOT need ghostview to see this!!)

Here we show that the idea of using quantum groups, Hopf algebras etc. to construct finite dimensional Hilbert spaces for our acclerating Universe, is not likely to work, at least with standard quantum group constructions. (And you do NOT need ghostview to see this!!)

Chethan Krishnan, Center for Relativity and The Weinberg Theory Group, Dept. of Physics, University of Texas, Austin.