String theory - more than just a 'theory of everything'?AlamyPosted on 07/22/2009 1:30:44 AM PDT by neverdem
Baroque field gets fresh lease of life in condensed-matter physics.
String theory - more than just a 'theory of everything'?AlamyUntil recently, string theory — long heralded as a 'theory of everything' — hadn't been particularly good at explaining anything.
But at a workshop this month at the Kavli Institute for Theoretical Physics in Santa Barbara, California, scientists have been using the theory to make progress in tackling one of the biggest puzzles in condensed-matter physics: the origin of high-temperature superconductivity.
String theory suggests that vibrating strings that exist in 10 dimensions underpin the observable Universe. Although that basic premise is still very much in doubt — and as yet impossible to test experimentally — some of the mathematical tools used in string theory have in the past few years been applied to describe the behaviour of hot particle plasmas and supercooled lattices of atoms.
The latest claim for string theory is that it is a key tool in explaining the normal behaviour of materials that conduct electricity without any resistance at relatively high temperatures. The theory that explains conventional superconductivity at temperatures close to absolute zero is well-developed — but the theory that explains the behaviour of a second class of materials, which can superconduct at temperatures as high as 70 K, remains something of a mystery. By explaining the normal behaviour of these materials just above their superconducting temperature, string theorists hope to get a better handle on high-temperature superconductivity itself.
"It suggests that we are on the verge of understanding a new state of matter using a string-theory description," says Subir Sachdev, a condensed-matter theorist at Harvard University in Cambridge, Massachusetts, who co-organized the workshop. At the workshop, Sachdev and his collaborators circulated a paper, as yet not even a preprint, in which they stake their claim to a string-theory model for high-temperature superconductors.
Finding new applications for the mathematics of string theory is reinvigorating the field, says Harvard University postdoctoral researcher Sean Hartnoll, another workshop co-organizer. "It now has the feeling of being a melting pot of ideas."
String theory started out in the late 1960s as a tool to explain the strong forces between nuclear atomic particles, but was replaced in the 1970s by the more successful quantum chromodynamics (QCD) theory. String theory went off in its own direction, acquiring ever more baroque layers of mathematical complexity. Some physicists found it anathema that the only way the resulting theories could be tested required energies far higher than those achievable in particle accelerators.
But in 2005, string theory did find its way, albeit indirectly, into one accelerator: the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory in New York. Scientists discovered that string theory could be as useful as QCD in explaining the strong nuclear forces involved in a quark–gluon plasma. This new state of matter, comprising the basic constituents of protons and neutrons, was created in the hot mash-ups of gold ions generated at the RHIC. The key to this discovery was a mathematical technique in string theory that embodies the principles of holography, in which information contained in a higher dimension can be embedded in one fewer dimensions — just as a three-dimensional image can be stored within a flat, two-dimensional hologram.
Since then, researchers such as Sachdev and Hartnoll have extended the holographic techniques to the cooler regimes of condensed matter. The same string-theory tools have helped to explain the behaviour of quantum critical points — the changes in matter cooled close to absolute zero when quantum mechanical effects start to dominate its behaviour.
That in turn has allowed physicists to describe the quantum behaviour of a variety of systems, including laser-induced lattices of supercooled atoms, and now high-temperature superconductivity.
Noted string theory critic Peter Woit, a mathematician at Columbia University in New York City, says that using string theory as a tool in these ways could be useful, but they are not tests of string theory itself. "Just because a model works in one context, doesn't mean you can unify physics and get a fundamental theory of reality," he says.
Joseph Polchinski, a string theorist at the Kavli Institute and the third conference organizer, argues that if the same string-theory tools used to describe black holes can help explain the behaviour of electrons in a metal, the crossover will enable string theory applications in one area to benefit other fields
The excitement is catching on, he adds. The institute received 110 applications for just 30 spots at the workshop — the toughest workshop to get into in his memory. Quite a feat given that when it was organized 18 months ago there were fewer than a dozen papers published on the topic. "It was clearly a good gamble," says Polchinski. "It's clear there's interesting new science here."
Add every number and every equation ever conceived, you have string theory. The resulting is garbage based on lies.
String theory predicts I have to use the bathroom in a few minutes. I don’t want to get up so we switch to M-theory.
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Fitting observation to a model is only the first part of theoretical physics. Prediction of as yet unobserved/unknown phenomena is the real test. Waiting.
Good language for a short proposal to obtain more grant funds for your favorite scientific pursuit. Tie your project to String Theory and the money flows. Propose something actually practical and it's a no-go. That is the state of science today. String theory is a pretty mathematics and poor science. But worse, it has become, like Global Warming, a new religion. IMHO it is well past the time when String Theory needed to be either proven or abandoned.
String theory answers the question of whether the universe actually contains anything stupider than the theory of evolution...
Oh the time these folks waste on trying to explain an illusion.
"String theory causes climate change."
Cheers!
Sounds like it could be an offshoot of the Flying Spaghetti Monster religion.
I've read a lot of explanations of 'string theory' and for the most part my feeble noggin can't quite grasp it. I wish it could, because this stuff does interest me. But at the same time, the more I read up on it the more I find it hard to believe that these same folks think we're nuts because we believe in God. ; )
Thanks for the article. Too bad it’s such a draw for the FR anti-science crowd.
Some Orthodox Jewish groups count 11 such dimensions and do not rule out yet others.
All of this may well be something that can be discussed in the same langauge.
Since "string theory" at this time is simply a mathematical language that enables us to discuss the interactions of the fundamental forces in the Universe, I'm not quite sure what their point is concerning it.
It's pretty obvious to me that it has a parallel/cognate language used in the Judeo-Christian tradition to discuss God, and that's pretty doggone profound. Consequently, it would seem to me that it would be much more likely for the anti-religion crowd to be against "string theory" than the religious minded.
Thanks for the link. There is another program, perhaps even more interesting, about High Temperature Superconductivity. The talks are as well rather technical, but check out the “Discussions of Issues Raised in the Conference” http://online.kitp.ucsb.edu/online/highertc09/
Or, maybe not. Modern theoretical physicists are usually pretty ignorant of a lot of things ~ current events, how government works, girls, stuff like that ~ and religion.
>>>Good language for a short proposal to obtain more grant funds
The ultimate, inescapable, and inevitable booogeyman someone throws into nearly all FR science threads. “Grants”.
I guess that which must be paid for is invalid. Just because.
I have no problem with grants. They are an obvious necessity if we want to support science, which I do. The problem isn’t with the grants themselves but with the process by which they are awarded. There is bias in the process that hurts scientific pursuit and “String Theory” is one of those popular buzzwords that helps you get funding. “Climate Change” is another. “Global Warming” used to work but it has fallen out favor (LOL).
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