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Steffen Gielen, Lucía Menéndez-Pidal.
Black Hole Singularity Resolution in Unimodular Gravity from Unitarity
Physical Review Letters, 2025; 134 (10)
DOI: 10.1103/PhysRevLett.134.101501i can’t even understand the very beginning of the discussion : why are physicists so obsessed with “information loss” ?
It has long been stated that a quantum theory of black hole dynamics that is required to be unitary must deviate strongly from semiclassical expectations. Usually this is discussed in the context of unitarity of black hole formation and evaporation, leading to the famous issue of information loss.[24]*
[24]* : S. W. Hawking, Breakdown of predictability in gravitational collapse
Phys. Rev. D 14, 2460 (1976).To oversimplify, “information” is a very specific thing in quantum physics. Classical physics has the rule that energy can change form but cannot either be created or destroyed.
Information works the same way in quantum physics, which makes black holes seem like a problem since their event horizons are inescapable and anything that falls inside is lost.
Thanks, your explanation is interesting and makes sense at my level of abstraction.
Eventually i would like it, if some physicist could come up with a cosmology where energy could be created and entropy of a close system could decrease … in specific conditions and in our present day universe.
Also, in my naive understanding, chaotic pendulums creates information.
“Information” in the quantum sense refers to waveform of the quantum system as a whole, which is kind of a weird thing to get one’s head around.
Even in the case of chaotic pendulums, there’s no theoretical principle that keeps us from observing and accounting for every particle and quanta of energy involved and using that to prove that the waveform of the entire pendulum is consistent with itself and the expected evolution from previous states.
But the event horizons of black holes seem to break that rule, because the waveforms of black holes can be described with just three properties; mass, charge, and spin. There didn’t seem to be “room” for them to encode all the waveforms of anything that falls inside until Stephen Hawking theorized that black holes gradually radiate away their energy, releasing their trapped information in the process.
This might be one of the worst, least-descriptive titles I’ve ever seen
