Oppenheim's Radical Bet: Gravity Isn't Quantum — SkimNews
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- Jonathan Oppenheim, a physicist at University College London, is developing a post-quantum gravity theory that treats space-time as continuous and indivisible, contradicting the mainstream view that gravity must ultimately be quantized like the other fundamental forces.
- In a July paper, Oppenheim and Zachary Weller-Davies at the Perimeter Institute in Canada showed that key space-time symmetries from general relativity can also be applied to post-quantum gravity.
- Oppenheim's model requires random fluctuations in space-time — causing clock ticks to wobble slightly — as the mathematical price of reconciling gravity with quantum mechanics, a feature he concedes he dislikes but calls unavoidable.
- Work published in May found Oppenheim's framework generates 'phantom' dark matter from those same space-time fluctuations, potentially reproducing some gravitational effects currently attributed to the unseen substance that outweighs visible matter 5 to 1.
- The theory also derives the Born rule — a foundational but unexplained postulate of quantum mechanics — as an output rather than an assumption, which Oppenheim argues addresses a century-old gap in quantum theory.
- In 2023, Oppenheim made a bet at 5000-to-1 odds with loop quantum gravity originator Carlo Rovelli (Aix-Marseille University) and string theorist Geoff Penington (UC Berkeley); if gravity is quantized he owes them 20p, if not they owe him £1000.
- Rovelli rejects the model as violating both quantum mechanics and general relativity, likening it to 'proposing theories in which the Earth does not rotate around the sun,' while Ivette Fuentes at Southampton argues any unification will inevitably have to break both pillars.
Why it matters: If Oppenheim's framework holds up, it offers a single conservative-looking model that simultaneously addresses two of physics' biggest unsolved problems — the quantum-gravity conflict and the nature of dark matter — while explaining why the Born rule works, all without invoking extra dimensions or strings. Even sceptics concede progress on unification will require breaking something fundamental, making his wager a live test of which pillar of modern physics gets sacrificed.
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