Infinite index extensions of local nets and defects

40th LQP Workshop "Foundations and Constructive Aspects of QFT"
Simone Del Vecchio on June 24, 2017

Extensions of a (properly infinite) von Neumann algebra can be described by Q-systems, introduced by Longo. If the extension is ""small"" (it has finite Jones index), the theory of Q-systems with its application to Quantum Field Theory is worked out by Longo and Rehren. We present a way to suitably extend some results to the case of infinite Jones index. In particular we show applications to extensions and defects in Quantum Field Theory. Joint work with Luca Giorgetti.