At What Point Does Spacetime Shift Into Quantum?
Summary
This PBS Space Time episode explores how researchers are probing the quantum-classical boundary by making gravity small and quantum effects large. It details modern refinements of the Cavendish experiment to test for deviations in Newtonian gravity at mesoscopic scales and examines optomechanics, including LIGO, to detect entanglement in macroscopic mirrors. The discussion highlights that these lab-based approaches offer a feasible path to observing the quantum nature of gravity without requiring massive particle accelerators.
Topics discussed
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Introduction: Quantum gravity and the mesoscale
The quantum-classical transition and experimental strategies
History of measuring the gravitational constant
Cavendish experiment and modern refinements
Challenges in measuring gravity at small scales
Vienna experiment: Tiny Cavendish setup results
Future prospects and quantum entanglement basics
Optomechanics and macroscopic entanglement
Using LIGO to detect quantum entanglement
Proposals for gravity-mediated entanglement
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