After Empty Promises, Will String Theory Find New Uses? (science.org) 38
Science magazine reports:
For decades, string theory promised a "theory of everything" that described all particles and forces as tiny vibrating strings. Physicists hoped it could also solve one of the field's deepest problems: reconciling quantum mechanics with gravity. But as string theory grew increasingly elaborate — and experimentally unreachable — many physicists lost hope.
Now, some researchers are revisiting the theory from first principles. In a paper in press at Physical Review Letters, Clifford Cheung, a physicist at the California Institute of Technology, and colleagues lay out a small set of assumptions about the universe and show that they inevitably give rise to string theory.... Cheung's study, along with another one posted to arXiv in January, starts with two reasonably conservative assumptions: that the probabilities of all possible outcomes of an event add up to 100%, and that the laws of physics are consistent for observers moving at different speeds. Each group then posits additional assumptions that have not been borne out by observations. Cheung's analysis invokes "ultrasoftness," the idea that the probability of certain particle interactions drops off at a particular rate at high energies. The second study, led by University of Michigan physicist Henriette Elvang, instead assumes "supersymmetry," a maximal coupling between matter and forces. Both groups conclude the only theory that can satisfy their assumptions is one that looks like string theory...
Cheung and Elvang stress that their aim is not to prove the inevitability of string theory. "I don't have a dog in the fight; I just work here," Cheung says. Rather, the goal is to explore the space of possible theories under rigid constraints — regardless of whether they reflect reality... The one thing the researchers all agree on is that the field would benefit from more alternative models to string theory. Cheung sees the agnostic, bottom-up exploration as a step in that direction. "You can either give up on the problem because it's too culturally toxic, or you can ask: If you want to find an alternative, what do you need?" he says. "Now, we know exactly what to do."
Thanks to Slashdot reader sciencehabit for sharing the article.
Now, some researchers are revisiting the theory from first principles. In a paper in press at Physical Review Letters, Clifford Cheung, a physicist at the California Institute of Technology, and colleagues lay out a small set of assumptions about the universe and show that they inevitably give rise to string theory.... Cheung's study, along with another one posted to arXiv in January, starts with two reasonably conservative assumptions: that the probabilities of all possible outcomes of an event add up to 100%, and that the laws of physics are consistent for observers moving at different speeds. Each group then posits additional assumptions that have not been borne out by observations. Cheung's analysis invokes "ultrasoftness," the idea that the probability of certain particle interactions drops off at a particular rate at high energies. The second study, led by University of Michigan physicist Henriette Elvang, instead assumes "supersymmetry," a maximal coupling between matter and forces. Both groups conclude the only theory that can satisfy their assumptions is one that looks like string theory...
Cheung and Elvang stress that their aim is not to prove the inevitability of string theory. "I don't have a dog in the fight; I just work here," Cheung says. Rather, the goal is to explore the space of possible theories under rigid constraints — regardless of whether they reflect reality... The one thing the researchers all agree on is that the field would benefit from more alternative models to string theory. Cheung sees the agnostic, bottom-up exploration as a step in that direction. "You can either give up on the problem because it's too culturally toxic, or you can ask: If you want to find an alternative, what do you need?" he says. "Now, we know exactly what to do."
Thanks to Slashdot reader sciencehabit for sharing the article.
I don't buy the assumptions (Score:3, Interesting)
"the probabilities of all possible outcomes of an event add up to 100%, and that the laws of physics are consistent for observers moving at different speeds." -- I'm neither a physicist nor a mathematician, but both of these seem debatable to me. If our notion of causality and time is correct, the first one might be true, but I've heard those things being questioned. And what 'requires' the laws of physics to remain stable? Those laws were formulated by scientists to explain things they don't fully understand. What if the scientists were wrong?
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"the probabilities of all possible outcomes of an event add up to 100%, and that the laws of physics are consistent for observers moving at different speeds." -- I'm neither a physicist nor a mathematician, but both of these seem debatable to me. If our notion of causality and time is correct, the first one might be true, but I've heard those things being questioned. And what 'requires' the laws of physics to remain stable? Those laws were formulated by scientists to explain things they don't fully understand. What if the scientists were wrong?
What if, indeed?
I suppose they'll continue to revise and refine their models, teaching, and textbooks as information arises. As science does.
You and I are as Bonobos weighing in on if the guys who designed the SR-71 are right about this flight thing. We're no more equipped to weigh in on quantum physics than my cats are to opine on the efficacy of mRNA vaccines. Science is a process and that process involves peer-review, and constant checking for flaws. This isn't multi-level marketing or religion w
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In other words, "Back off, man! I'm a scientist."
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"the probabilities of all possible outcomes of an event add up to 100%
Many Worlds Interpretation.
the laws of physics are consistent for observers moving at different speeds
Why wouldn't they be consistent? Do the orbits of the planet change whether you are on the Vogager probes or standing on Earth? Does a drop of water form a sphere differently on the ISS than in the Vomit Comet? If the laws of physics changed dependent on one's speed, the universe would be truly fucked. [wikipedia.org]
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No. It's more that each photon is matched up with a anti-photon aka the photon being absorbed.
There's no such thing as 'time' and the universe doesn't diverge at every possible moment.
It's just a bit....fuzzy. If you look closely.
Re:I don't buy the assumptions (Score:4, Interesting)
If the scientists are wrong, they will eventually figure out that they're wrong and fix it: that's how science works. For example: Abberation (astronomy) [wikipedia.org]. That article contains a paragraph that explains how stellar aberration was observed, explained incorrectly, explained better - but still incorrectly, and eventually explained correctly. Science is designed to be self-correcting, and while sometimes those corrections are difficult and contentious, they inexorably happen.
The assumptions you list are made by physicists because (a) we have no experimental evidence that they're wrong and (b) we have a mountain of experimental evidence demonstrating that they're right. If that changes, if even a single bit of experimental evidence shows that they're wrong then (1) someone will win a Nobel Prize and (2) science will apply the correction. But I strongly doubt this will happen.
As to string theory: my own feeling is that we may be only a few years from being able to conduct experiments that might invalidate it. Please read carefully: I'm not predicting that they will, I'm predicting that they will be capable of doing so. If I'm right about that, and those experiments are run, then either (a) they won't invalidate string theory, leaving the door open for more discussion and research, or (b) they will invalidate string theory. Of course if the latter happens, the people who've invested so much of their lives working on it will be very disappointed -- but because they're scientists, they'll accept it.
Rather than write more about this, I'm going to quote Carl Sagan: "The Cosmos is all that is or was or ever will be. Our feeblest contemplations of the Cosmos stir us -- there is a tingling in the spine, a catch in the voice, a faint sensation, as if a distant memory, of falling from a height. We know we are approaching the greatest of mysteries."
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If the scientists are wrong, they will eventually figure out that they're wrong and fix it: that's how science works.
In science,the way "wrongness" is fixed is by experiment. The only way to decide one way or the other is to collect more data.
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No, these are not self-evident, you are correct about that. Unpacking the second assumption, what we now have to ask is what would a universe like that look like if the proposition is untrue?
We have two kinds of possibilities: (1) There is a unique frame of reference that is special and superior to all others, or (2) there is >1 special frame of reference that is superior to most frames of reference (but this becomes difficult to imagine how 2 or 3 or more especially special frames of reference do not e
That's handy, the assumptions aren't for sale. (Score:2)
I think, you've missed the purpose of the paper.
It isn't trying to prove a 'theory' about the universe, it's trying to describe the shape of space that all possible theories live in, for the given assumptions.
There's nothing requiring the laws of physics to remain stable and the team aren't trying to imply their is.
They're saying "if" the laws of physics to remain stable across different energy levels, scales etc, than these things we need to think ab
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Oh, and they are saying that String Theory is a theory that fits in the space of possible theories - it would be really nice to have a different theory to compare.
supersymmetry has to go (Score:4, Funny)
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Um, I think Dark Energy is basically a general acknowledgement of an uneven topology. It'll take a lot more to gain any definition though.
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A flat universe is the logical default assumption, even if everyone understands it might be wrong. If you are going to posit a non-flat universe you have to come up with...something...to describe the non-flatness, such as Dark Energy.
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It's shaped like a giant KKK hat. Purely coincide, I assure you.
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Who is "Will String" and why does she have a theory?
I'm thinking (Score:2)
After "The Big Bang Theory" we should have "The String Theory". Something to do with g-strings and pole dancers perhaps. Or pulling strings for favours in various governmental bodies? Or something entertaining.
It's over. (Score:2)
Tell Sheldon once and for all that "It's over!"
Nikola Tesla said it (Score:4, Informative)
He said if you want to find the secrets to the universe you have to think in terms of energy, frequency, and vibrations. Which, at its most base level, is what String Theory tries to do. Not saying he's right, but the overlap is interesting.
probabilities adding up? (Score:3)
Vala: There's a seventy percent chance that if we dial manually we will be able to establish a connection, and a fifty percent chance that the bomb will just go off.
Mitchell: That's a hundred and twenty percent.
Vala: Well, there's some crossover where we establish a connection and the bomb goes off.
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Has there ever been a sci-fi series where they were on the last season and the writers ended up explaining the end of everybody being from a ghastly mistake?
Old News (Score:2)
Claude 4.9 has already solved this.
String theory and falsifiability (Score:3)
Physics has used indirect testing for many years, and I don't think anyone expected string theory to be any different.
There are research papers that detail specific properties that must be present in any string theory-based model of gravity, for example. If we find, in our efforts to study quantum gravity, that those properties can't hold, then string theory cannot be correct. Not just a specific string theory, ANY string theory at all.
Any string theory that requires a supersymmetry that is reachable by the LHC once it gets updated will be falsified within a very short space of time. If we persist in not seeing supersymmetry after this further round of updates (and we've already had several to improve luminosity), then none of the string theories involved can be correct. They have to be false.
None of these allowing string theory would prove string theory "true", but if any are false then string theory cannot be true. If ALL of them permit string theory, then whether or not string theory describes anything real, the maths that has been done must nonetheless describe real things.
Black Holes? (Score:2)
From what I understand on the topic (which is laughingly little) is that you need to know what's going on inside a black hole to reconcile quantum and classical physics. I hear this repeatedly over and over again. If this is the case then how can string theory ever be resolved?
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No. (Score:2)
No, it wonâ(TM)t. It has been a waste of time for decades.
Scientists invent more and more dimensions , hallucinating harder than a 2022 LLM.
In the end it did nothing.
Only Game In Town (Score:3)
String Theory has contributed some useful mathematics but its position as the Only Game In Town (they call it that) appears to have been a psyop to keep Academia out of the work being done at private contractors.
Retired people from e.g. Skunkworks have described corrections and extensions of Maxwell's Equations and the Dirac Equation as the path that has yielded experimental success.
Those guys didn't "shut up and calculate". Their work is under NDA, WUSAP, ITAR, and Invention Secrecy Act restrictions.
Some parallel work, e.g. Exodus Technologies, has started to bear fruit in the public domain, so the psyop is being wound down now. Additionally China has surpassed the US in implementation so they want All Hands On Deck.
What was strategic advantage has become a strategic liability. One can understand this mindset by not caring about the hundreds of millions of lives that could have been saved by resultant technologies. When only State Supremacy (and COG) are factored in the normal human behavior goes out the window.
The impossible need to power AI for a communist surveillance police state may also be playing a factor; hard to know prospectively but somebody has the power source being demonstrated on the slow drip of DoD "UFO" videos.
Most people won't put Space Aliens on the top of the list of culprits when ATS projects by humans will suffice.
The biggest hurdle will be getting Deans and Department Chairs to discard their life's work as meaningless. What a "Good Scientist" should do and what most people will do are not the same. Hence the "funeral to funeral" adage.
Re: Only Game In Town (Score:3)
You're off your meds again, Bill?
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The aliens abducted Bill's meds. Not Bill's fault.
related to the three types of time theory? (Score:2)
Does anyone know if this is overlaps or is related at all to the idea that there are three types of 'time' for different scale interactions? Which I vaguely half-remember.
I will read the article when it is not past my bedtime.
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Oh Holy FSM, we worship thee!
most of space "science" is garbage (Score:2)
A string walks into a bar (Score:2)
Where all cosmology theories end up (Score:2)
It will morph into Dark String Theory in 3...2...1...