Posted on 12/26/2007 9:45:58 PM PST by camerakid400
A "universe in a test tube" that could be used to assess theories of everything has been created by physicists.
The test tube, the size of a little finger, has been cooled to a fraction of a degree above the lowest possible temperature, absolute zero, which is just over 273 degrees below the freezing point of water.
Does one of these test tubes hold a baby Universe? Inside the tube an isotope of helium (called helium three) forms a "superfluid", an ordered liquid where all the atoms are in the same state according to the theory that rules the subatomic domain, called quantum theory.
What is remarkable is that atoms in the liquid, at temperatures within a thousandth of a degree of absolute zero, form structures that, according to the team at Lancaster University, are similar those seen in the cosmos.
"In effect, we have made a universe in a test tube," says Richard Haley, who did the work with Prof George Pickett and other members of the "Ultra-low Temperature Group."
The Holy Grail of physics is to establish an overarching explanation to unite all the particles and forces of the cosmos. But one of the complaints commonly levelled at a leading contender for a "theory of everything", called string theory, is that it is impossible to test.
But now, according to the study in the journal Nature Physics, it may be possible using the universe in a test tube. "It was a serendipitous discovery," says Haley.
The equations used to describe this superfluid turn up in many other branches of physics. "For instance, the internal structure of the superfluid mirrors very closely the structure of space-time itself, the 'background' of the universe in which we live," says Haley.
"Consequently the superfluid can be used to simulate particle and cosmic phenomena; black holes, cosmic strings and the Big Bang for instance.
"This is great for testing theories, since the equations describing helium-3 are well-established enough to say that it is the most complex system for which we already have the 'Theory of Everything'," Haley continues.
"If the analogous experiments don't work in helium-3, then it's probably time to go back to the drawing board (or computer) with your latest pet theory."
Since the pioneering work of Albert Einstein, the quest for a theory of everything has depended on combining theories of the very small (quantum theory) and the very large (relativity).
One of the strangest features of such theories is that they require the universe to have more than three spatial dimensions to unify our picture of all forces and all matter. One promising candidate is supersymmetric string theory, in which ripples on strings are interpreted as particles. But, to their surprise, physicists found five superstring theories. Now the Lancaster experiments provide new insights into the phenomena predicted by these theories.
For the past three decades it has been known that strings are one member of a bigger class of objects called branes, which exist in higher dimensional space, that could be extended in more than one dimension - from strings of one dimension, to membranes of two dimensions, to those of p dimensions, dubbed p-branes. Moreover string theories and p-branes are facets of one underlying 11-dimensional M theory, which suggests that we live in a brane world: a four-dimensional surface, or brane, in a higher dimensional mixture of space and time.
People and most particles move in the brane, while the higher dimensions provide a framework to unify all forces, from gravity to those that act between atomic particles. While experiments have begun to highlight cracks in the current best theory, called "the standard model", there is evidence that M theory's extra hidden dimensions could be revealed next year when a Geneva atom smasher - the £4.4 billion Large Hadron Collider - begins experiments. But the Lancaster team offers another route to address this impasse.
One idea is that a collision between a brane and an antibrane could have triggered the Big Bang itself. This can now be simulated in superfluid helium within the little test tube.
Trying to understand this is making my brane hurt...
Our universe could be in some cosmic test tube
Reminds me of the ending to “Men in Black”:
http://www.youtube.com/watch?v=1QPll-TKaEE&feature=related
You gotta watch this video on String theory:
it may make your ‘brane’ hurt more but its worth it
Not really, time-space becomes non-local below the Planck length, ie... the microcosm is finite.
Actually ... If there are large extra dimensions, the measured strength of gravity may be much smaller than its true (small-scale) value; in that case the Planck length would have no physical significance, and quantum gravitational effects would appear at much larger scales.
OK.
Taking a tube of liquid matter and freezing it to almost absolute zero slows down the energy vibrations to almost zero. Were they to slow to absolute zero, they would cease to exist.
But, at that slow speed, the makeup,flow, density of the particles,atoms, molecules, etc. resemble our best estimates of the makeup,flow,density of the stars,galaxies, planets, etc.
Wouldn’t it be cheaper to just order an envelope of Sea-People?
“the microcosm is finite.”
Nope. One can approach, but can never actually reach 0.
Something I have always known to be true, but was afraid to say it.
Oh, swell.
This is on the wrong track. Most of the electrons in most of the matter around us, for example, are in effect frozen to absolute zero. That is, they are in the "ground state" where they cannot give up energy, and in fact it takes a considerable amount of energy to "excite" them, so that this happens rarely. The commonplace inhabitance of the ground state suffices to refute your notion of existential cessation, I think.
The mass of atoms is largely contained in the nuclei, and the rules of QM show that it takes relatively little energy to excite them into motion. It is only at sub 1 Kelvin temperatures that collections of atoms coalesce into a macroscopic "ground state" and it is in this state that the weird and wild laws of QM introduce their cosmic analogies.
Thank you for responding in such an informative manner.
I respect your admirable knowledge of the subject, so I will do my best to keep up with you. Unfortunately I don’t have the obvious background in QM that you seem to.
“The commonplace inhabitance of the ground state suffices to refute your notion of existential cessation, I think.”
Well, since achieving absolute zero is impossible, then we will never know if matter ceases to exist. Since I can’t prove a negative with a negative, I iz refuted.
But I get points for the pun.
So, I guess you agree with me? Cause I thought I said that.
Well, regression towards absolute zero is on a logarithmic scale, as reflected in the homily, “There is as much physics between 1/1000 K and 1/100 K as there is between 100 K and 1000 K”. As you get colder and colder, smaller and smaller excitations get “frozen out” and more and more subtle interactions come into play. It’s like “The man who shrank”.
In this logarithmic way of thinking, there’s no question of “reaching” absolute zero, so you could say that “ceasing to exist” at absolute zero is just a melodramatic formulation of the Third Law.
I was pointing out that this is not really a compelling idea since we can see the effects of being “frozen out” in the electronic states of atoms, and they do not involve “winking out” of existence.
hum, need to quit my day job and take up brane theory
That would be the poor joker who married my first wife. At least she'll have less of him snack on!
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