Wednesday, June 9, 2010

The Universe as an example of Spontaneous Symmetry Breaking? Nah!

Though I doubt if anyone could really believe what I am going to speculate about here, it is perhaps an interesting idea. Let me add that I may not have thought of this myself, but may well have read about it in some of the speculative cosmology and physics books.
In answer to the famous question “Why is there something and not nothing?” might we suppose that it is an example of what in modern physics is called “Spontaneous Symmetry Breaking” (SSB)?
SSB is a simple but elegant idea, and is usually illustrated by the image of a pencil balanced on its tip over a flat surface. The pencil of course wants to fall to a position of lower potential energy, and when released it will “choose’ an angle to fall to on the flat surface. Note that the initial position on its tip is perfectly cylindrically symmetric about the axis of the pencil (make the idealization that the surface is infinite and perfectly flat and smooth, and the pencil is perfectly symmetric about its axis). But—here is the odd thing---the later, lower energy, state of the pencil is not cylindrically symmetric.
In physics terms, one says that “the ground state of the system does not have the symmetry of the dynamical expression that describes the initial state of the system (technically, this expression is called the Hamiltonian of the system).
Other more complex examples of SSB are ferromagnetic alignment when a sample of iron is cooled below the Curie temperature, and the Higgs Boson that will be sought after by experiments on the LHC. But these will not be considered in this short note.
The point is, imagine a “state of nothingness”. Well, ha ha, we probably really can’t, but maybe we can at least try. In any case, it would seem that a state of nothing possesses a high degree of symmetry: No direction in space could be defined (even if there were space), no angles or orientations can be imagined, etc. In fact, it seems that “nothing” represents perfect symmetry in every sense. Now the actual physical Universe does not seem to be as symmetric as “a state of nothing” is symmetric. Could it be that in some sense, “a state of nothing” involves a tension, an energy, that is just not stable, and it must “fall” (in some unimaginably complex hyperspace) to a lower energy consisting of a bunch of random stuff—i.e., a vast collection of matter and energy, a Universe? Well, as I said at the outset, I can’t buy this, but it is at least an amusing speculation.

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