PIRSA:19120037

Video URL

https://pirsa.org/19120037

Dueling Arrows of Causality, Causal Uncertainty and Quadratic Gravity

Donoghue, J. (2019). Dueling Arrows of Causality, Causal Uncertainty and Quadratic Gravity. Perimeter Institute for Theoretical Physics. https://pirsa.org/19120037

Donoghue, John. Dueling Arrows of Causality, Causal Uncertainty and Quadratic Gravity. Perimeter Institute for Theoretical Physics, Dec. 11, 2019, https://pirsa.org/19120037 

          @misc{ scivideos_PIRSA:19120037,
            doi = {10.48660/19120037},
            url = {https://pirsa.org/19120037},
            author = {Donoghue, John},
            keywords = {Quantum Foundations, Quantum Gravity, Quantum Information},
            language = {en},
            title = {Dueling Arrows of Causality, Causal Uncertainty and Quadratic Gravity},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2019},
            month = {dec},
            note = {PIRSA:19120037 see, \url{https://scivideos.org/pirsa/19120037}}
          }

John Donoghue University of Massachusetts Amherst

Talk numberPIRSA:19120037
DOI10.48660/19120037
Source RepositoryPIRSA
Collection
Talk Type Conference
Subject

Abstract

Quadratic gravity is a renormalizeable theory of quantum gravity which is unitary, but which violates causality by amounts proportional to the inverse Planck scale. To understand this, I will first discuss the arrow of causality in quantum field theory (with a detour concerning the arrow of time), and then discuss theories with dueling arrows of causality. But the causality violation might be better described by causality uncertainty. This is discussed both in quadratic gravity and in the effective field theory of general relativity.