When I visited IAS earlier in the year, Witten was sorting out Lieb's (nontrivial) proof of strong subadditivity. See also Big Ed.
A Mini-Introduction To Information Theory
This article consists of a very short introduction to classical and quantum information theory. Basic properties of the classical Shannon entropy and the quantum von Neumann entropy are described, along with related concepts such as classical and quantum relative entropy, conditional entropy, and mutual information. A few more detailed topics are considered in the quantum case.
Notes On Some Entanglement Properties Of Quantum Field TheoryYears ago at Caltech, walking back to Lauritsen after a talk on quantum information, with John Preskill and a famous string theorist not to be named. When I asked the latter what he thought of the talk, he laughed and said Well, after all, it's just linear algebra :-)
These are notes on some entanglement properties of quantum field theory, aiming to make accessible a variety of ideas that are known in the literature. The main goal is to explain how to deal with entanglement when – as in quantum field theory – it is a property of the algebra of observables and not just of the states.