PIRSA:19120037

Dueling Arrows of Causality, Causal Uncertainty and Quadratic Gravity

APA

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

MLA

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

BibTex

          @misc{ 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},
            year = {2019},
            month = {dec},
            note = {PIRSA:19120037 see, \url{https://pirsa.org}}
          }
          

John Donoghue University of Massachusetts Amherst

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.