Wednesday, April 06, 2011

[Books] Book Look: Quantum Reality, by Nick Herbert

Book Look: Quantum Reality, by Nick Herbert: I guess you can consider this part 2 of my continuing forays into the wackness that is reality. The last month was an exploration of the nature of time, reaching back to the beginning of the universe. This time it's all about the meaning of Quantum Theory.

Quantum Theory is the most audacious and intellectually challenging concept ever devised. It addresses a known situation wherein a particle doesn't exist in until it is observed or measured. Now, let's be clear on that. It's not that we don't know it's if it's there or not until we look at it, it is that is literally doesn't exist. OK, that's not exactly true, but in the common sense of existing, it doesn't. It exists in a bizarre state called a probability wave in which it is in all possible places we could see it at once. Only when we look does it settle into a particle in one spot.

Bizarre and surreal. Yet it is true. It is going on around us all the time, these particles popping into reality. The best discussion I know of on this idea is a lecture from Richard Feynman (made available courtesy Microsoft, you may need to view it in IE). It's worth watching if you're curious about this.

So you see what I mean about wackness. This makes the theory of relativity seem positively tame.

Early in the twentieth century a number of scientists (Werner Heisenberg is the big name here, but he was one of many who had a hand) came up with Quantum Theory to deal with this. It is an enormously complicated set of laws based on something called waveform physics, which generates exact answers to all experimentation done in the quantum realm. In other words, we know exactly what rules govern this stuff -- verified by experiments over and over again in the ensuing years. We can make very accurate predictions about what will happen when and where, but we don't really know what it means as far as the nature of reality. I mean, really, what is this nonsense about being in all possible places at once?

This is what Nick Herbert tries to sort out. In the end he can't, of course, because it's not something that is known. (In fact, some make the argument that it can't be known.) So he has to settle for reviewing the possibilities. Unfortunately, many of possibilities devolve into very unsatisfying conclusions. Herbert does a thorough job, but let me shortcut to a few interesting ones.

Observer Created Reality -- this is the new age notion that, in a very real sense, reality as we know it is created when we observe it. Now, that leaves wide open the question of what counts as observation. Einstein belittled this by saying (paraphrased) that he could not imagine a mouse having some creative control over the universe. At least one physicist has proposed quite scientifically that reality only occurs when it comes into purview of intelligent consciousness. This leads to the view of the universe as a lattice of interconnected observations, outside of which there are only probability waves. If a tree falls in the forest and nobody sees it, did it really fall? The answer is, apparently, there is no tree only the probability of one.

Many Worlds -- this was conceived in the early sixties. It stems from the whole notion that unobserved particles exist in all possible states prior to observation. One thing that quantum physicists are really keen on is finding a way that there is nothing special about our existence. If ours is one existence that occurred out of an uncountable number of possible turns the universe could have taken over its life, that leaves these guys having to figure out why this one instead of the others. So if these bizzare quantum things exists in all possible places prior to being observed, why did they just happen to end up the way they did? (As a gambler, this problem doesn't bother me. Bad beats happen. Trust me on this.) The many worlds theory gets around this by saying they all happen, you just can't see the others because they exist in a parallel universe. Then science fiction writers figure out ways around that and we get Sliders and Spock with a beard.

Action at a Distance -- not really a conception of Quantum Reality but a fact that must be accounted for, and frankly, it gets my gold star for the single weirdest thing in the universe. Also called quantum entanglement, this tells us that unconnected things can have "knowledge" of each other. It is possible to get two particles in a state such that they mirror each other. Imagine two particles one charged negative and one charged positive (it's not really a charge, but think of it that way for the sake of argument). If you put these particles in an "entangled" state, when one particle changes charge the other also does at the same instant. The key thing is that there is no need for one particle to indicate the change to the other; it's as if they are physically connected. The kicker is it doesn't matter how far apart they are. They could be the full instance of the known universe apart and they would still change instantaneously. This, as Herbert points out, is essentially voodoo. Stick a pin in a doll in Haiti and some poor schlub in Peoria screams in pain. Except with entangled particles it actually happens. It looks like in some sense, everything in the universe is connected as if it were a single object. I hate that. It makes me feel like I'm in some kind of hippie-mystic acid trip.

Einstein never warmed to Quantum Theory. Of the unobserved universe being created of probability waves, he famously said (paraphrase), "God does not play dice with the universe." He was less adamant in time but always felt that it the notion of the quasi-existential, probabilistic state required of a particle prior to observation was untenable. Even as more and more experimental validation came he never gave in. In the end the best he could argue was that the universe is really made up a normal stuff and the Quantum Theory is incomplete. That there is something else to it that we have yet to discover that makes the numbers work out for the normal stuff of the universe without resorting to the wackness. Interestingly, a group of people called the neo-classists have tried to do just that, but to account for Action at a Distance they have had to resort to something going faster than the speed of light, which Einstein proved impossible.

As you can tell, the bottom line here is that nobody has a friggin' clue about the essential nature of the world we live in. We can predict what will happen in specific circumstances quite well. Perhaps even better that when Issac Newton sorted the world out back in the day. Because of this we can make use of the nature of things without actually knowing the story behind them. But on the objective nature of Reality, our ignorance is monumental.

Herbert does a clear, precise cataloging of the theories, their proponents, and their shortcomings. He does not talk down nor does he gloss over issues. He chooses an unconventional demonstration of observer created reality using polarization of light through a crystal which is more than a bit confusing. I highly recommend the Feynman lecture linked above for that demonstration. He also goes into some detail about the sorts of experiments that are done to validate Quantum Theory, but I could not follow them.

Should you read Quanum Reality? If you have a passing familiarity with this topic and while you've read or seen a bit about it, you still don't know what it all means, then yes. Herbert is at his best when trying to dig into what all this means rather than the experimental justification. At that he excels. If you have little or no knowledge of quantum theory, I don't recommend this as a starting point. More popular recent works by someone like Brian Greene or Paul Davies would be a better place to start. But do try to get here eventually; it's an eye-opener to our ignorance. And in the end, while Herbert has his favorite ideas, like every other physicist, one suspects that he realizes that at the moment, the metaphysical theories just reflect the pre-existing human bias of the scientists involved. The truth is, we just don't know, and we may not for may many years to come. My guess is that when we are resorting to the stuff of fantasy and sci-fi, we are probably as far from having any answers as we have ever been.