String Theory Journal Club

The Quantum Null Energy Condition (QNEC) is the statement that information in QFT is physical: a minimum amount of energy is required to process a given amount of information. Formally, QNEC bounds the null-null component of the energy-momentum tensor in terms of the von Neumann entropy. After a brief review, I will show that in the context of quenches in 2d CFTs, QNEC implies a generalization of the Clausius inequality, placing bounds on entropy increase in terms of temperature increase. I will then describe ongoing work on a proof of Rényi QNEC in general QFTs: casting the problem in an operator algebraic framework, I will show how Rényi QNEC reduces to an integral over QNEC in the Rényi parameter, up to a crucial technical obstruction. I will close with an outlook on resolving this obstruction.