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Exploring Superstrings in the Lab
ultracool writes "Physicists at Utrecht University in the Netherlands have come up with a way of observing a superstring by utilizing Bose-Einstein condensation (BEC). A one-dimensional BEC in an optical lattice is rapidly rotated, causing a quantized vortex to form. The bosonic part of the superstring consists of this vortex line. Inside the vortex, they would trap an ultracold cloud of fermionic atoms. Hopefully this will allow observation of the supersymmetry between bosons and fermions, thus providing the first experimental evidence to support superstring theory."
I almost understood a word of that.. Almost.
http://java.sun.com/j2se/1.5.0/docs/api/java/lang/ StringBuilder.html .
They're great. You can modify them and they aren't synchronized so they're fast, too. If these scientists are only just now discovering them they should try reading some newsgroups.
A more detailed explanation of http://en.wikipedia.org/wiki/Superstringssuperstri ngs.
Supersymmetry between bosons and fermions is not possible in your universe. We have seen to that.
It's the one in which Q inverts a universal constant, right?
...to refer people to more information on Bose-Einstein condensates (BEC):
BEC wikipedia page
BEC home page at Colorado
BEC at NIST
What is a BEC?
this is the first experiment that could confirm the existence or non existance of super strings. This would begin to give emperical evidence to support String Theory. up until now most work on String Theory has been unable to provide a working way to test it. this could easily change the face of theoretical physics in the labs and particle accelerators.
Any string theorists out there want to chime in?
This has direct implications for the food industry. No longer will superstring cheese have to be refrigerated, the fermionic atoms will maintain an ultracold cloud around the superstring cheese, keeping it tasty and fresh. Yum.
Even those who arrange and design shrubberies are under considerable economic stress at this period in history.
If they can demonstrate that the predictions of superstring theory hold true, and that it can actually be used to connect Quantum Physics with Relativistic Physics, we might actually be able to stop some of the bickering that goes on among Physicists today.
What does that mean for us? Well, when Newton found physical laws that worked more generally than Aristotle thought, Physics was born and we were launched into a new era of science. Einstein's Special (and then, afterward) General Relativity made what we consider the modern era possible.
Quantum Physics and Relativity have always been at odds, though. After all, what makes gravity operate at a quantum level? Superstring theory is one of several "theories of everything" that would allow us to explain the world in more general terms--and in the past, every time that has happened, society and technology has taken leaps and bounds forward.
What will happen if we find out that Superstring theory really is the theory of everything? It's liable to be as outlandishly unthought of as space travel to the people of the turn of the 20th century.
Now, for the reason: if you know some quantum physics, think of taking two composite objects and interchanging them; fermions wavefunctions change sign under this interchange. For the composite object, its wavefunction looks like (an anti-symmetrized) product of single-particle wavefunctions. If those are fermionic and there are an odd number of them in the composite wave function, interchanging the two composite wavefunctions will produce an odd number of sign changes in the product, for an overlal sign change. If there are instead an even number of fermionic single-particle wavefunctions in the composite wavefunction, the resulting even number of sign changes under interchange produces no net sign change in the many-body wavefunction.
This is easily extended to composite objects that are a composite of both bosons and fermions.
To use a computational analogy, they are simulating the equations of string theory using a BEC as the computer. So whatever results they get had better agree with string theory! They aren't actually testing whether these explain the world, just exploring the equations of string theory with an efficient computer -- the BEC.
http://www.pbs.org/wgbh/nova/elegant/program.html
All 3 hours of it are avaliable on PBS's website.
It's amazing stuff.
The book "The Elegant Universe" by Brain Greene is what the TV Special above is based on.
Definitly worth a look at - if you enjoy the TV special, have a look around for the book... It goes into a LOT more detail.
"Who says nothing is impossible? Some people do it every day!" - Alfred E. Neuman
A liquid or solid condensate at room temp exhibiting BEC properties will be nice. I wonder if liquid helium can be made that way.
If you can flow liquid helium up your arm at room temperature, it's time to talk to your landlord ASAP.
Caveat Emptor is not a business model.
Intrastellar space is not ultracold, it's pretty darn hot (4 Kelvin) when you contrast that to the temperatures needed to form a BEC (around 170 nanoKelvin).
So what's the definition of a fermion or a boson, and in this specific case, of a fermionic or bosonic nucleus?
Bosons have integer spin, and fermions have half-integer (n+1/2, where n is a nonnegative integer) spin. The spins of the individual quarks in nucleons (protons and neutrons) always add up to a half-integer, so nucleons are fermions. The quarks themselves are too. The spins of the nucleons in a nucleus can add up in different ways, depending on the number of each kind (proton and neutron) present. When the spins add to become an integer, the nucleus is bosonic. When the spins add to a half-integer, the nucleus is fermionic.
If a given nucleus is fermionic, then identical nuclei of that type obey the Pauli exclusion principle. If the nucleus is bosonic, then the Pauli exclusion principle does not apply to it, and the possibility of a collection of that kind of nucleus forming a BEC exists.
"It is nice to know that the computer understands the problem. But I would like to understand it too." --Eugene Wigner
So this is very cool (literally!) science, but NOT a test of superstring theory as a way to describe fundamental particles or interactions. At best, it will provide some interesting checks of the mathematical predictions of string-like theories, but only translated into this system. You still won't know if string theory has any hope of describing real electrons, photons, gravitons, etc.
IAAP (I am a physicist), and again we have an physics article posted by someone who doesn't know the difference between reality and an analogy.
The system that these folks propose to study (quantized vorticity in a Bose-Einstein condensate) can be described with the same type of mathematics that is used in superstring theory. The proposed experiments would test the validity of the math. These experiments would say nothing about whether the math of superstring theory is a valid description of the world!
A similar situation would be the following: observing a weight on a spring would confirm the math behind simple harmonic oscillators. It would not, however, tell me anything about whether the vibrational modes of the sun obey those same equations.
Analogy != equivalence!
Good scientitst might have a good feeling, a hunch, but are ready to be disproved so they can move on, because a negative value is just as good as a positive (if not as exciting).
:)
That beleive stuff is for tooth fairies and god(s)
There's nothing Intelligent about Intelligent Design.