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|u/MistWeaver80 Permalink:
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|u/jamcultur - 17 hours
|
|Too bad the article is behind a paywall.
|u/luttman23 - 17 hours
|
|Yeah, could anyone post the article text?
|u/nujuat - 12 hours
|
|This is the preprint of the letter they cite in the article
|https://arxiv.org/abs/2307.08133
|u/djasonpenney - 10 hours
|
|Or more directly, https://arxiv.org/html/2307.08133v5
|u/xanderlearns - 18 hours
|
|I thought gravity was just an inherent trait of the curvature of space-
|time, rather than a "force"?
|u/ChipotleMayoFusion - 17 hours
|
|That is correct according to General Relavivity, which is the current
|best physics model for describing gravity and spacetime. This model is
|not mathematically compatible with Quantum Physics, which is the best
|model for subatomic interactions, and also explains electromagnetism.
|So GR covers big things and gravity, QM covers small things and
|electromagnetism. Unfortunately nobody has figured out how to put
|them together. A key difficulty in learning about how they meet is
|that situations where gravity and electromagnetism or nuclear forces
|both matter will inherently be very extreme, like the center of a
|black hole. For a given mass of stuff the electromagnetic force is
|like 10^50 times stronger, so it's very hard to think up an experiment
|where you precisely measure how the two interact, and that can
|actually be constructed.
|u/DarthArcanus - 6 hours
|
|The best part is how Quantum Mechanics and General Relativity are
|two of the most well tested and proven theories in all of physics.
|And they're mutually exclusive. If General Relativity is absolutely
|true and complete, Quantum Mechanics breaks down, and vice versa.
|One of these two theories is incomplete.
|u/ChipotleMayoFusion - 6 hours
|
|Yeah, it's a fantastically frustrating situation, because it is so
|hard to imagine how we can make experiments to probe the overlap.
|Like we need to learn how to make black holes or something. Also
|who knows when it will be solved, maybe next week someone comes up
|with a new idea, and if it has a testable prediction, the boom it
|could be solved. Who knows.
|u/Tricky_the_Rabbit - 56 minutes
|
|I'm putting my bet on some combination of modulatable mass using
|electric charge or kinetic energy alongside gravitational
|detectors not unlike LIGO or else dark matter detectors such as
|supercooled xenon. LIGO is amazing! It's a hack allowing
|measurement of distance fluctuations on the atto scale (10e-18m)
|by shooting a laser and detecting changing in the color,
|corresponding to changes in the frequency of the wave that must
|be caused by the squashing and stretching of spacetime. While
|the gravitational waves it detects produced by black hole
|mergers, they are also astronomical distances away. It stands to
|reason that mass modulation that "in the same room" would be
|within the range of detection by larger LIGO-like detectors.
|This at least opens the door for gravity experiments.
|u/fartiestpoopfart - 13 hours
|
|this might be a stupid question but is it possible that the two
|simply can't be unified?
|u/ElvenMartyr - 11 hours
|
|The universe exists. It does stuff. Whatever the universe does/is
|is the unification. There's no guarantee that that process has a
|simple mathematical description, though there are reasons to
|believe that it likely does.
|u/SimoneNonvelodico - 10 minutes
|
|It would be funny if the solution was "literally any situation
|in which that would matter is by definition hidden behind an
|event horizon so there's no answer". (I know that's a bit of a
|stretch and I meant it mostly as a joke, though I can imagine
|there might be a more sophisticated genuine "cosmic censorship"
|model that could be built)
|u/ChipotleMayoFusion - 8 hours
|
|In the current form, they can't be unified, but what people are
|trying to adjust the math in ways that would be possible to unify
|and still fit with all the various measurements across both
|models. Physics models are based on some assumptions and math
|that describes something. Simple example, let's say you have a toy
|train on a track and tou want to describe it with some models.
|Imagine in Model A you assume the train track is a single loop and
|a single train that can move forwards and backwards. Imagine Model
|B where you describe the train as a fluid that flows downhill, and
|the train can be split into multiple separate parts that can all
|flow down hill in different directions. This fluid Model B can
|also handle if the track splits into multiple paths. Now these
|two models overlap in some situations, but they use such
|fundamentally incompatible assumptions that you can see they won't
|agree in some situations. General Relativity and Quantum
|Mechanics are like this, they both describe some set of behavior
|very well, but the regions where they both make predictions are so
|extreme that we can't generally do any experiments to understand
|what is going on.
|u/JimblesRombo - 13 hours
|
|they can't !! we're going to have to use a mix of hard-to-get
|experimental data from colliders and deep-space telescopes, along
|with creative new mathematical frameworks to update one or both of
|the theories to a form where they stop disagreeing with both each
|other, and the universe. as i understand it, quantum field theory
|has a better track record in its domain than GR has in its
|u/Patelpb - 16 hours
|
|All of the other forces are explained well by field theories and force
|carriers (i.e. the EM field communicates coulomb force via photons,
|which are really just ripples in the EM field anyways) It's not clear
|whether gravity has a similar trait with a force carrier. Plenty of
|theories suggest a graviton could exist, which would be to the
|gravitational field/spacetime as photons are to the electromagnetic
|field. This is where the divide occurs, more or less
|u/xanderlearns - 16 hours
|
|Interesting. So in the EM field, where photons are particles, what
|I'm hearing you say is that the particles themselves are wave
|packets rather than discrete particles? Which would mean that we're
|looking for, but have yet to find, gravitational wave packets in a
|gravitational field?
|u/Patelpb - 16 hours
|
|Overall fair interpretation >particles themselves are wave
|packets rather than discrete particles? They are wave packets
|with discrete energy, which is often referred to as being a
|discrete particle depending on the context >Which would mean that
|we're looking for, but have yet to find, gravitational wave
|packets in a gravitational field? Yes, at least that's one
|proposed explanation. It could very well be the case that some
|unimagined idea explains gravity on the quantum scale, but
|spacetime curvature doesn't seem to offer useful explanations at
|that scale. However, since ALL of the other forces have a field
|theory with force-carrier particles, one can't help but wonder if
|the only other major force does too. Sorry for being so obviously
|biased haha
|u/xanderlearns - 16 hours
|
|No, that's super helpful! I thought I understood previously, but
|wouldn't the carrier being a "wave packet" necessarily imply a
|discrete energy? Like if the definition of the packet was
|bounded, then wouldn't the energy be calculated from the
|frequency+wavelength within those bounds?
|u/3z3ki3l - 13 hours
|
|Look in to [vacuum
|energy](https://en.wikipedia.org/wiki/Vacuum_energy), and
|specifically the [vacuum expectation value](https://en.wikiped
|ia.org/wiki/Vacuum_expectation_value). Basically even when
|there’s nothing there, there’s still a measurable value of the
|chance that something *could* be there. Which kinda indicates
|it’s not all that discrete, and the lower bound isn’t all that
|low. Edit/also: actually the page on the [Casimir
|effect](https://en.wikipedia.org/wiki/Casimir_effect) might be
|more helpful for the EM field.
|u/xanderlearns - 8 hours
|
|Yeah...always bothered me that we claim to "know the speed
|of light in a vacuum" when we've never even measured a TRUE
|vacuum, completely devoid of even energy...
|u/3z3ki3l - 8 hours
|
|Well there’s the question of whether that could even
|exist. Once you remove everything, what holds its
|existence? If vacuum is empty space that is capable of
|holding the possibility that something *could* be there,
|once you remove that possibility… why would it be there?
|Kinda like how zero doesn’t exist; no objects exist with a
|quantity of zero. If you managed to suck out *everything*,
|then it very well might collapse into nothing. The real
|value of vacuum energy, to us, is determining whether we
|can grab hold of it. Just like how you can’t sit in a
|rowboat in the middle of a lake and move without an oar to
|push off the water, if we could learn to “push” off of the
|vacuum, then we get into all kinds of crazy sci-fi
|territories. FTL, gravity manipulation, power generation…
|the fun stuff.
|u/Tricky_the_Rabbit - 50 minutes
|
|This is bringing back vague recollections of a few
|articles I read which claimed that information is either
|as fundamental as mass and energy, or possibly that
|information is to energy as energy is matter. One
|article claimed that even after the universe has
|attained thermal equilibrium, informational equilibrium
|would still be zillions of years away. It also makes me
|think about CCC, and how a decayed universe in which
|everything is so spread out it can't interact or else do
|decayed it's massless and therefore timeless is actually
|a universe which is, topologically, identical to a
|pointlike timeless pre-universe before a big bang. XD
|We're too clever for our own good.
|u/CocaineIsNatural - 7 hours
|
|> Which would mean that we're looking for, but have yet to find,
|gravitational wave packets in a gravitational field? It was the
|photoelectric effect, think solar panels, that led to the
|discovery of photons. And it was Einstein that figured it out.
|Here is an article on it -
|https://www.britannica.com/science/photoelectric-effect I am sure
|there are youtube videos that cover it as well, if you prefer a
|more visual coverage of it.
|u/Dihedralman - 13 hours
|
|The key is Quantum Field Theory which treats all forces by fields
|inherent to space time. Particles themselves interact on these fields,
|and the fields have mediators. Mathematically, gravity doesn't look
|special in that respects. However, as the other poster points out
|it is far weaker. And in the standard equations mass is treated
|differently so it doesn't act like a monopole charge. Reformulation of
|the equations can resolve this and people have done that, but there
|are issues and experimental verification is key- for it to fit within
|QFT as other fields we would need to measure the graviton.
|u/SimoneNonvelodico - 9 minutes
|
|The main reason why we describe it as curvature of space-time is that
|it acts on everything the same way and given that it's essentially
|easier to describe it that way. You can very well describe it as a
|force too, but it gets all much more complicated (it's complicated
|enough as is). If we ever found something to which gravity does *not*
|apply, or applies differently or in reverse, then we would have to go
|back to describing it as a force.
|u/PhilosophicWax - 15 hours
|
|I believe this is the source material:
|https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.133.180201
|It has the same author.
|u/CocaineIsNatural - 7 hours
|
|And a simplified article on it -
|https://phys.org/news/2024-11-gravity-quantum-entity.html
|u/QVRedit - 18 hours
|
|Sounds interesting, though I don’t know just how it would work.
|u/luttman23 - 17 hours
|
|That's why scientists do what they do
|u/whit9-9 - 16 hours
|
|Isn't it superimposed? Or did you just have a gaffe?
|u/SkeetySpeedy - 13 hours
|
|I think they mean it as typed - “posed” like “in position” A crystal
|in superposition would be, grammatically at least, “superposed”
|u/whit9-9 - 13 hours
|
|Oh. If so then I made the gaffe.
|u/moderngamer327 - 4 hours
|
|If this is actually possible this would be absolutely revolutionary for
|physics. The biggest obstacle in physics right now is the lack of
|ability to test quantum and gravitational interactions
|