[The University of Texas at Austin: What starts here changes the world]
Theory Group
Theory Group Special Seminar, 27 September 2016


Dr. Sandipan Kundu, Cornell University

Causality constraints in conformal field theory

abstract

Causality places nontrivial constraints on QFT in Lorentzian signature, for example fixing the signs of certain terms in the low energy Lagrangian. In conformal field theory, I will show how causality is encoded in crossing symmetry and reflection positivity of Euclidean correlators, and derive constraints on the interactions of low-lying operators directly from the conformal bootstrap. Then, I will explain the connection between these causality constraints and the averaged null energy condition. Finally, I will use causality to show that the averaged null energy is positive in interacting quantum field theory in flat spacetime.



This page was last updated on 5 January 2016
Texas Cosmology Center   ♦   Physics Department   ♦   University of Texas at Austin