Steffen Gielen, Lucía Menéndez-Pidal. Black Hole Singularity Resolution in Unimodular Gravity from Unitarity
Physical Review Letters, 2025; 134 (10) DOI: 10.1103/PhysRevLett.134.101501
i 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]*
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.
My buddy is a PhD candidate and he’s heavily involved in black hole research, I’m not even going to try to summarize it because when he talks to me it’s like me watching a finger puppet play.
One of the things he talks about is how The jury is still out on if energy is even real.
The problem is that it’d be like if matter and energy could just disappear. Black holes would be exclusively tiny, as soon as one formed it’d start vanishing anything that crossed it’s event horizon rather than growing, so galaxies could never have formed as their cores would just shrink away as soon as they got too dense.
Black holes are regions of space where information density hits the upper limits allowed by physics. Add more information to it, and the event horizon expands proportionally to what was added. With that in hindsight, it seems rather obvious that the boundary of the event horizon could encode the information once thought to be lost to the black hole inside.
It could do that but what’s the evidence that it does? Or has someone proved this is already a feature of semi-classical gravity that just wasn’t noticed before? Or is it only a feature of a brand new hypothetical theory?
How deep do you want to go into this, and what’s your level of familiarity with the Holographic Principal and AdS/CFT corrospondance? There’s no hard evidence yet but there is a shitton of circumstantial evidence to suggest that this is what happens.
Steffen Gielen, Lucía Menéndez-Pidal.
Black Hole Singularity Resolution in Unimodular Gravity from Unitarity
Physical Review Letters, 2025; 134 (10)
DOI: 10.1103/PhysRevLett.134.101501
i can’t even understand the very beginning of the discussion : why are physicists so obsessed with “information loss” ?
[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.
My buddy is a PhD candidate and he’s heavily involved in black hole research, I’m not even going to try to summarize it because when he talks to me it’s like me watching a finger puppet play.
One of the things he talks about is how The jury is still out on if energy is even real.
at my level of comprehension : https://libquotes.com/aristotle/quote/lbd3b5p
To say of what is that it is not, or of what is not that it is, is false, (…)
→ Aristotle
if you want to get serious, read @[email protected] in this post.
why’s it a problem? why can’t information just be lost at a black hole?
The problem is that it’d be like if matter and energy could just disappear. Black holes would be exclusively tiny, as soon as one formed it’d start vanishing anything that crossed it’s event horizon rather than growing, so galaxies could never have formed as their cores would just shrink away as soon as they got too dense.
Black holes are regions of space where information density hits the upper limits allowed by physics. Add more information to it, and the event horizon expands proportionally to what was added. With that in hindsight, it seems rather obvious that the boundary of the event horizon could encode the information once thought to be lost to the black hole inside.
It could do that but what’s the evidence that it does? Or has someone proved this is already a feature of semi-classical gravity that just wasn’t noticed before? Or is it only a feature of a brand new hypothetical theory?
How deep do you want to go into this, and what’s your level of familiarity with the Holographic Principal and AdS/CFT corrospondance? There’s no hard evidence yet but there is a shitton of circumstantial evidence to suggest that this is what happens.