It is known that thermalization in a CFT corresponds to black hole formation in AdS space. For a system to thermalize it must interact. To address black hole formation in string theory we look for thermalization in the D1D5 CFT which has an AdS dual. Thermalization should occur through interactions caused by twist operators which deform the theory off of its free point. The twist operators can join and unjoin ‘strings’ in the CFT. No clear evidence of thermalization was identified at first order in the twist deformation. We therefore compute interactions at second order in the twist deformation with an initial excitation propagating on one of the strings. We consider transitions of the initial excitation to three lower energy excitations in the final state. This yields preliminary evidence for thermalization.

I review the reformulation of the AdS/CFT correspondence as

a quantum error correcting code, and explain how this gives a new

perspective on several mysterious features of the correspondence, in

particular the Ryu-Takayanagi formula.

In 4D CFT, the anomaly coefficient c is the coefficient of an anomaly in scale transformations. In this talk, we show how scale anomaly coefficients such as c can be computed in terms of CFT data, namely the operator spectrum and OPE coefficients. We obtain expressions for the anomaly coefficient using Euclidean position space and Minkowski momentum space. The latter gives the coefficient in terms of a positive-definite sum over states, but may suffer from UV and IR divergences. We confirm our expressions by explicit calculations for anomalies involving scalar operators. Along the way, we show how to do calculations in Minkowski momentum space using the state-operator correspondence, a technique which may have many other applications.