Sunday, January 30, 2011

Something About Nothing

From Nothing: A Very Short Introduction by Frank Close.

"Our immediate experiences are of bulk matter and our senses are blind to the existence of atoms, but clues to the restless agitation of the atomic architecture are all around. As I watch my plants grow I don't see the carbon and oxygen atoms pulled from the air and transformed into the leaves; my breakfast cereal mysteriously turns into me because the molecules are being rearranged. In all cases the atoms are calling the tune and we lumbering macro-beings see only the large end-products...

"Many physical systems do not show the fundamental symmetries of the forces that build them. Electromagnetic forces don't care about left or right, yet biological molecules have mirror images that are inert or even fatal while their originals are food or beneficial.

"Balance a perfectly engineered, cylindrically shaped pencil on its point. Turn around: it looks the same. This invariance when one rotates is known as a symmetry, in this case rotational symmetry. Balanced on its tip the pencil is metastable as the force of gravity will pull it to ground if it is displaced from the vertical by the slightest amount. The gravitational force is rotationally symmetric, which implies that when the pencil falls to the ground, no particular direction is preferred over another. Do the experiment thousands of times and the collection will show the pencils have fallen to all points on the compass, in accord with the rotational symmetry. However, on any individual experiment you cannot tell in which direction the pencil will fall; having fallen, perhaps to the north, the 'ground state' will have broken the rotational symmetry. Roulette is another example. Play long enough and all the numbers will win with equal likelihood; this guarantees that the house wins as the zero is theirs. But on any individual play, it is your inability to predict with certainty where the ball will fall that is the source of the gamble.

"In the example of the pencil, the state in which the symmetry is broken is more stable than the symmetric state in which the pencil was precariously balanced on its tip. In general, the laws that govern a system have some symmetry but if there is a more stable state that spoils it, the symmetry is 'spontaneously broken', or 'hidden'. So it is with a snowflake and water, or with magnetism of iron.

"You may cry foul at this point arguing that this is not really a failure of symmetry, but more a result of one's imprecision in balancing the pencil: 'The pencil dropped because it was not perfectly upright.' This is true, but suppose that it has been balanced on a perfectly engineered point. Even then, the atoms in the tip are in random motion, due to the heat manifested in their kinetic energy. This randomness means that the direction of toppling is random. You might agree, but suggest that we do the experiment at temperatures approaching absolute zero of temperature, -273º C, where the kinetic energy tends to vanish. Your gedankenexperiment supposes the tip to be engineered from perfectly spherical molecules, the pivotal one being frozen in place at absolute zero temperature where thermal motion has ceased. The catch is that the quantum laws take over. If motion has vanished, then position is unknown and the point of balance is itself randomized. If the point were precisely known at some instant, motion would be undetermined and the resulting imbalance unpredictable. It seems that here, and in general, the quantum fabric of nature enables high-energy metastability to choose a state of lower energy where the symmetry is spontaneously broken. Thus melting ice, or heating magnetized metal, causes the symmetry to return, but when allowed to cool again, the symmetry is broken with no memory of what happened before. The rule is that raising the temperature causes structure and complexity to melt away, giving a 'simpler' system. Water is bland; ice crystals are beautiful.

"The universe today is cold; the various forces and patterns of matter are structures frozen into the fabric of the vacuum. We are far from the extreme heat in the aftermath of the Big Bang, but if we were to heat everything up, the patterns and structures would disappear. Atoms and the patterns of Mendeleev's table have meaning only at temperatures below about 100,000º; above this temperature atoms are ionized into a plasma of electrons and nuclear particles as in the Sun. At even hotter temperatures, the patterns enshrined in the Standard Model of particles and forces, where the electron is in a family of leptons, with families of quarks and disparate forces, do not survive the heat ... the electromagnetic force and the weak nuclear force that controls beta-radioactivity melt into a symmetric sameness. Theories that describe matter and forces as we see them in the cold imply that all these structures will melt away in the heat. According to theory, the pattern of particles and forces that we are governed by may be randomly frozen, accidental remnants of symmetry breaking when the universe 'froze' at a temperature of about 10^17 degrees. We are like the pencil that landed pointing north, or the roulette wheel where the ball landed in the slot that enabled life to arise. Had the ball landed elsewhere, such that the mass of the electron were greater, or the weak force weaker, then we would have been losers in the lottery and life would not have occurred."

"Here I have come full circle back to my starting conundrum. If the spontaneous symmetry breaking had made other parameters and forces, we would not have been here to know it. This has given rise to the radical idea that there may be many vacua, multiplicities of universes, of which ours is the one where by chance the dials were set just right."

"An example here is of magnetized metal: heat it, destroying the magnetism, and cool it again. In one part the atomic magnets become frozen together pointing in one direction, while in another part of the metal they lock in another direction. This phenomenon is known as 'magnetic domain'. Could this be a model of the universe? Theorists have built mathematical models of the Big Bang, which have to agree with what we know and exhibit the 'true' symmetry in the early hot epoch. A general feature seems to be that such models imply that when cooling occurs from the initial symmetric state, there is a 'landscape' of possible solutions. When you view the entire landscape, you see on the average the original symmetry: like the orientations of the fallen pencil at all points of the compass, there are all possible masses and forces that are consistent with the original symmetry. What is true hereabouts, and in the billions of light years accessible to us, might be different elsewhere."


This can lead us to conclude that we experience the universe's current state simply because we exist. We see what we see because these are the only conditions that allow it. The possibilities held in every moment are reduced to a singularity by our presence. This is natural selection on the quantum level. We are birthed from the random: endless possibilities have come and gone in the wake of our presence, leaving only one experience of reality that is entirely observer-dependent. Randomness rules every aspect of our lives, but ultimately, only one result prevails that is dependent on our mode of perception. In light of relativity, every observer lives their own personal version of the universe with their own perception of time: our own place in a vibratory, multidimensional mandala. Though some of our experiences can overlap in symmetry, we find that we are God playing dice, the Brahman playing hide-and-seek with itself, creating uniqueness in every moment, now ad infinitum. We find polarities unified: chaos and order, difference and similarity, organism and environment, unity and separateness, something and nothing, as sides of the same coin. They create each other and depend on each other. All arises together, in and of itself.

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