Irreversibility in Quantum Field Theory: An Information-Theoretic Perspective

A deep property of quantum field theory is the irreversibility of the renormalization group flow: as we move to longer length scales, the number of relevant degrees of freedom only decreases. In this colloquium, we will show how ideas from quantum information theory provide a new understanding of this irreversibility. A key role is played by the distinguishability of states, and by fundamental limits on reconstructing a state associated to a larger region from states in smaller ones. These methods give unified proofs of irreversibility in two, three, and four space-time dimensions, and generalize to systems with impurities or defects. This talk will also discuss conceptual lessons and open questions suggested by the information-theoretic approach to quantum field theory.

Speaker: Gonzalo Torroba, Instituto Balseiro, Argentina