If you follow the late breaking news about Quantum Mechanics, like I do, you are aware that a new experiment called the “Afshar Experiment” has set Quantum on its ear. A new experiment, which seems to refute a couple of the Quantum Theory interpretations, has been described and its results have been replicated. Read about it in John Cramer’s column at Analog.
Quantum Mechanics, however, is still correct and the only way to describe mathematically the behavior of very small things. What has changed is the way we explain what is happening. You see, the problem with Quantum Mechanics is that there seems to be no Mechanics. Various schools of thought try to interpret the results of the mathematics try to envision some sort of clockwork mechanisms behind the behavior of electrons and photons and their ilk. Quantum Mechanics is like Vonnegut’s Cat’s Cradle – no Cat and no Cradle. There’s no Quantum and no Mechanics.
There is the Copenhagen School and the Many-Worlds view and a few other interesting ways to explain what we can’t see and will probably never understand. The two I mentioned may have been falsified. I will mention the caveat that Cramer has an alternative interpretation that was not falsified, so he has a stake in the Afshar Experiment holding up under intense scrutiny. It is not decided that Copenhagen and Many-Worlds are indeed out, but it looks like they might be.
Ah, the politics of Quantum Reality. “Quantum Reality”, by the way, is the title of a truly cool book by Nick Herbert that was written a few years ago (1987), but things happen slowly in Quantum Mechanics, so it is still a good read. I highly recommend this book as it is the best explanation of the World of Quantum Interpretations. Explaining Quantum Mechanics is a sort of religious endeavor and indeed many of the schools of thought smack of theology.
To me, it all comes down to St. Thomas Aquinas and his exploration of the prime mover. God is not a creature. God must go beyond pure causality. In this sense, there is no prime cause of things. There is no clear chain of actions that results in any outcome. Quantum Mechanics seems to prove that Aquinas was right, that Quantum interpretations seem to say that time, space and the reason why things happen aren’t necessarily related. In a kind of backwards logic, Quantum Mechanics makes it easy to believe in God.
Nick Herbert describes Bell’s Theorem at the end of his book. This is the spookiest part of Quantum. Bell’s Theorem seems to show that REALITY IS NOT LOCAL. You’ve heard the old chestnut about a butterfly flapping its wings in China causing a storm in Africa a week later. Bell’s Theorem seems to show that a butterfly flapping his wings on a planet a million light years away causes a breeze in Milwaukee the year before the wings start to move. The cause of things is not limited in space or time!
My favorite image of Bell’s theorem is that the act of looking up at the stars changes what you see, even though the light left the stars millions of years ago.
If you think that this sounds weird or spooky, you have hit on the inscrutable nature of Quantum Mechanics. Basically, it appears that we are not allowed to know the clockwork that makes things work. Suddenly God is a better physicist than we ever thought!