March 11, 2026

John Donoghue: The Physicist Who Says We've Already Quantized Gravity

1 hour 6 minutes

Professor John Donoghue explains why quantum physics and gravity actually work perfectly together. He tackles quadratic gravity, effective field theory, and random dynamics, arguing that grand unification and naturalness aren't required for a theory of everything.

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TIMESTAMPS:

- 00:00:00 - Limits of Quantum Mechanics

- 00:06:35 - Effective Field Theory

- 00:12:24 - Gravity: Geometry or Force?

- 00:18:46 - QFT and Gravity Tension

- 00:24:59 - Quadratic Gravity Theory

- 00:34:16 - Dueling Arrows of Causality

- 00:41:57 - Random Dynamics and Anti-Unification

- 00:48:13 - The Naturalness Problem

- 00:53:40 - Questioning Hidden Assumptions

LINKS MENTIONED:

- John's lectures: https://www.youtube.com/@johndonoghue469/featured

- John's papers: https://arxiv.org/a/donoghue_j_1.html

- The Renormalization Group and Critical Phenomena [Paper]: https://www.nobelprize.org/uploads/2018/06/wilson-lecture-2.pdf

- Anthropic Considerations in Multiple-Domain Theories [Paper]: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.80.1822

- Old "Ghost" Theory of Quantum Gravity Makes a Comeback [Article]: https://www.quantamagazine.org/old-ghost-theory-of-quantum-gravity-makes-a-comeback-20251117/

- Unitarity, Stability and Loops of Unstable Ghosts [Paper]: https://arxiv.org/pdf/1908.02416

- An Effective Field Theory of Gravity for Extended Objects [Paper]: https://arxiv.org/abs/hep-th/0409156

- Not Quite a Black Hole [Paper]: https://arxiv.org/pdf/1612.04889

- On Quadratic Gravity [Paper]: https://arxiv.org/pdf/2112.01974

- Quadratic Gravity [Paper]: https://arxiv.org/pdf/1804.09944

- Renormalization of Higher Derivative Quantum Gravity [Paper]: http://www.weylmann.com/stelle.pdf

- Quantum Theory in a Nutshell [Book]: https://www.amazon.com/Quantum-Field-Theory-Nutshell-nutshell/dp/0691140340

- Field Theory: A Modern Primer [Book]: https://www.amazon.com/Field-Theory-Modern-Frontiers-Physics/dp/0201546116

- Origin of Symmetries [Book]: https://amzn.to/4qxnLzj

- String Theory Iceberg [TOE]: https://youtu.be/X4PdPnQuwjY

- Neil Turok [TOE]: https://youtu.be/zNZCa1pVE20

- Avshalom Elitzur [TOE]: https://youtu.be/pWRAaimQT1E

- Sir Roger Penrose [TOE]: https://youtu.be/iO03t21xhdk

- Ted Jacobson [TOE]: https://youtu.be/3mhctWlXyV8

- Leonard Susskind [TOE]: https://youtu.be/2p_Hlm6aCok

- Jonathan Oppenheim [TOE]: https://youtu.be/NKOd8imBa2s

- Peter Woit [TOE]: https://youtu.be/TTSeqsCgxj8

- Joseph Conlon & Peter Woit [TOE]: https://youtu.be/fAaXk_WoQqQ

- Michael Levin [TOE]: https://youtu.be/c8iFtaltX-s

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By Theories of Everything

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