Study Finds Flaw In Emergent Gravity (phys.org) 50
An anonymous reader quotes a report from Phys.Org: In recent years, some physicists have been investigating the possibility that gravity is not actually a fundamental force, but rather an emergent phenomenon that arises from the collective motion of small bits of information encoded on spacetime surfaces called holographic screens. The theory, called emergent gravity, hinges on the existence of a close connection between gravity and thermodynamics. Emergent gravity has received its share of criticism, however, and a new paper adds to this by showing that the holographic screen surfaces described by the theory do not actually behave thermodynamically, undermining a key assumption of the theory.
In the new paper, the scientists tested whether different kinds of surfaces obey an analogue of the first law of thermodynamics, which is a special form of energy conservation. Their results reveal that, while surfaces near black holes (called stretched horizons) do obey the first law, ordinary surfaces -- including holographic screens -- generally do not. The only exception is that ordinary surfaces that are spherically symmetric do obey the first law. As the scientists explain, the finding that stretched horizons obey the first law is not surprising, since these surfaces inherit much of their behavior from the nearby horizons. Still, the scientists caution that the results do not necessarily imply that stretched horizons obey all of the laws of thermodynamics. On the other hand, the finding that ordinary surfaces do not obey the first law is more unexpected, especially as it is one of the key assumptions of emergent gravity. Going forward, researchers will work to understand what this means for the future of emergent gravity, as well as explore other possible implications.
In the new paper, the scientists tested whether different kinds of surfaces obey an analogue of the first law of thermodynamics, which is a special form of energy conservation. Their results reveal that, while surfaces near black holes (called stretched horizons) do obey the first law, ordinary surfaces -- including holographic screens -- generally do not. The only exception is that ordinary surfaces that are spherically symmetric do obey the first law. As the scientists explain, the finding that stretched horizons obey the first law is not surprising, since these surfaces inherit much of their behavior from the nearby horizons. Still, the scientists caution that the results do not necessarily imply that stretched horizons obey all of the laws of thermodynamics. On the other hand, the finding that ordinary surfaces do not obey the first law is more unexpected, especially as it is one of the key assumptions of emergent gravity. Going forward, researchers will work to understand what this means for the future of emergent gravity, as well as explore other possible implications.
Re:Emergence is innate (Score:4, Informative)
Huh,? Every quanta has angular momentum. Motion, as it were, is a fundamental property of the universe.
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Every quantum has angular momentum. All quanta have angular momentum.. Angular momentum, at the quantum level, does not involve motion, it involves spin, which is very difficult to describe as motion for an individual quantum or subatomic particle.
[ Yoiur grammar police hearing will be on the 31 day of Octember: Please contact the court clerk to pay your fine of 700 quatloos in advance. Should you choose to dispute the charge, the Pedantic Pedagogery Patrol can be reached via this entabgled connection. Warn
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Not the 31nd?
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Octember normally only has 29 days anyway. I'm not sure what you're so upset about.
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Octember normally only has 29 days anyway. I'm not sure what you're so upset about.
What if it happens to be a leap month?
Then the reverse is true.
Re:Are we in a simulation??? (Score:5, Informative)
The flaw here is a physical theory, basically the theory that the universe is holographic.
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"Assume a spherical cow."
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Finally (Score:3, Funny)
Finally, someone has explained the thermodynamics issue in emergent gravity theory re holographic screen surfaces using layman's terms to underscore the current scientific controversy in a clear, simple, easy-to-understand way that I nonetheless have no idea what the f----
The Problem with Theoretical Physicists (Score:3, Informative)
This article highlights the main problem with theoretical physicists. They are arrogant, and lack basic understanding of proper use of language. For example, the flaw identified in the paper is not with "Emergent Gravity", but with a specific attempt at an emergent gravity theory. The flaw is with the "holographic screens" theory. Now some idiot will go around claiming that "emergent gravity" is flawed. This is just one example out of a million like this. You can find similar examples in almost every discussion about Quantum Theory -- self delusion through poor use of language, perhaps intentionally so.
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Sounds like a physics degree program should include a rigorous linguistics course.
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The theoreticians don't come across as arrogant at all. To your point, the article specifically mentions that the emergent gravity theorists will need to work to resolve this issue, and that their work gives insights into other areas, and may be helpful for people doing other work (like quantum gravity). This in fact sounds deeply collaborative to me!
BTW, i'm not a theoretician, but i've spent a fair bit of time around various theoretical physicists, and the practical variety too, and they are to a person g
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Generally correct. He should probably have been blaming the reporter or the editor. Of course, I don't know in the particular case.
Often this misuse of the language is due to an editor insisting that the story be shortened, or at least that was once the case.
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Suit yourself but I'm starting to tie things down in case that 'stupid' flaw causes them to start floating away.
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If you ask me what "holographic screens" are, it certainly won't be anything related to physics...
Sabine Hossenfelder (Score:5, Informative)
Read her book. She is a theoretical physicist calling out the supersymmetrical intellectual dream fantasy wanking that theoretical physics has become: book is called âsLost in Mathâ . It is a great read.