Black holes-- Entropy container or creator?

Event Date:
2026-10-06T14:00:00
2026-10-06T15:00:00
Event Location:
HENN 318
Speaker:
William G. Unruh, University of British Columbia
URL:
zoom
Related Upcoming Events:
Gravity Seminars
Intended Audience:
Everyone
Local Contact:

Massie Eghtesad MASc, PMP
GRAIN Project Manager
Department of Physics & Astronomy 

zoom https://ubc.zoom.us/j/66265650702?pwd=aRKiSzTc1tWxN73g70AlsS5JV5MiyC.1 
Meeting ID: 662 6565 0702 / Passcode: 309051

Event Information:

Abstract: 

In 1974 Hawking argued that black holes emitted energy and entropy, with a total emitted entropy in its lifetime equal to 1/4 of the surface area of the horizon of the black hole. The usual analog is a lump of coal, which starts out at absolute zero, and is heated up by incoming energy. It slow radiates its energy and entropy over its lifetime. I argue that a better model is an amplifier, which has no intrinsic entropy but creates entropy (and energy) in its output as it amplifies. I.e., a black hole does not contain entropy but rather creates it, with its total entropy radiated equal to the 1/4 of the horizon area (in Planck units).

Bio:

William (Bill) Unruh was born in Winnepeg, Canada, and received his Phd at Princeton in 1971 under John Wheeler (also the advisor of Richard Feyman and Kip Thorne). He has for a long time been a Professor in the Dept of Physics and Astronomy at the University of British Columbia (UBC). He was also the founding director of the Cosmology and Gravity program of the Canadian Institute for Advanced Research.

Bill’s main research work is in quantum gravity. In trying to understand the quantum mechanics of black holes, Unruh discovered what is now called the Unruh effect (viz., that an accelerated detector in the vacuum sees a thermal bath, instead of seeing nothing) and the existence of the Unruh vacuum around black holes. His work has focused on the overlap between quantum mechanics and gravity, leading to work on the nature and measurement of time, the study of non-locality in quantum mechanics, the quantum origin of matter in early cosmology, the impact of quantum mechanics on the detectors of gravitational waves, and many other effects in the same general area. He has also worked on decoherence in quantum computation.

Bill is a Fellow of the Royal Society, of the American Physical Society, and of the American Association for the Advancement of Science.

 

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Add to Calendar 2026-10-06T14:00:00 2026-10-06T15:00:00 Black holes-- Entropy container or creator? Event Information: Abstract:  In 1974 Hawking argued that black holes emitted energy and entropy, with a total emitted entropy in its lifetime equal to 1/4 of the surface area of the horizon of the black hole. The usual analog is a lump of coal, which starts out at absolute zero, and is heated up by incoming energy. It slow radiates its energy and entropy over its lifetime. I argue that a better model is an amplifier, which has no intrinsic entropy but creates entropy (and energy) in its output as it amplifies. I.e., a black hole does not contain entropy but rather creates it, with its total entropy radiated equal to the 1/4 of the horizon area (in Planck units). Bio: William (Bill) Unruh was born in Winnepeg, Canada, and received his Phd at Princeton in 1971 under John Wheeler (also the advisor of Richard Feyman and Kip Thorne). He has for a long time been a Professor in the Dept of Physics and Astronomy at the University of British Columbia (UBC). He was also the founding director of the Cosmology and Gravity program of the Canadian Institute for Advanced Research. Bill’s main research work is in quantum gravity. In trying to understand the quantum mechanics of black holes, Unruh discovered what is now called the Unruh effect (viz., that an accelerated detector in the vacuum sees a thermal bath, instead of seeing nothing) and the existence of the Unruh vacuum around black holes. His work has focused on the overlap between quantum mechanics and gravity, leading to work on the nature and measurement of time, the study of non-locality in quantum mechanics, the quantum origin of matter in early cosmology, the impact of quantum mechanics on the detectors of gravitational waves, and many other effects in the same general area. He has also worked on decoherence in quantum computation. Bill is a Fellow of the Royal Society, of the American Physical Society, and of the American Association for the Advancement of Science.   Learn More: View some of Bill's talks on the Perimeter Institute website: https://pirsa.org/speaker/bill-unruh  See his bio on the Quantum Gravity website: https://quantumgravitysociety.org/science_advisors/william-unruh/  Read his Associate Fellow page on CIFAR: https://cifar.ca/bios/william-g-unruh/    Event Location: HENN 318