Tuesday, May 12, 2009

Changing the past

I had a revelation the other day. A full up, light came on, jaw dropped open revelation of how utterly astonishing the universe is. I tried to tell my wife about it, but she just shrugged and said "I knew that".

I was thinking about the Bell continuum. This is the strange place where all things happen simultaneously, because there is no time. The name comes about from the Bell Theory, which is itself an offshoot of the Pauli Exclusion Principle. Let me explain from the start.....

Way back in the history of quantum mechanics (about the time my Dad was born), a physicist named Wolfgang Pauli explained the fact that you could never see two electrons in the same orbit around an atomic nucleus by postulating what became known as the Pauli Exclusion Principle. It states that for electrons in a single atom, no two electrons can have the same four quantum numbers, that is, if n, l, and ml are the same, ms must be different such that the electrons have opposite spins.

The Pauli Exclusion Principle is what keeps subatomic particles distinct and separate from each other. If two particles did have the same quantum numbers, they would actually be the same particle. It has applications in electronics (semiconductors) and astrophysics. By insisting that particles must remain distinct one from another, it implies that things can only be compressed by certain amounts. The Principle is in fact what prevents my fingers from passing through the keyboard I am typing on, despite that fact that both are largely empty space.

It also says (in complex math that I won’t try to do here!) that if a particle spontaneously is created, that the sum of all its attributes combined with the other particles created from the same event is zero – all the quantum numbers add up to nothing, just as my high school teachers said I would.

John Bell extended this work and postulated the creation of 2 “entangled” particles, which he then separated and sent to mythical Alice, and mythical Bob. Alice and Bob didn’t measure anything about their particles, but one stayed home while the other flew to the other side of the world.

At exactly the same time, as they have agreed to previously, they measure one of the particle’s quantum properties, such as spin (s). The strange thing is that according to quantum mechanics (the Heisenberg Uncertainty Principle, which I have discussed earlier), the particle that Alice has is in an undetermined state until it is measured – it doesn’t actually have a spin, it has both spins until the observer measures it. That’s how a photon can go through two slots at once. When measured, it “selects” an output, and exhibits a given spin number.

Because of entanglement, the other particle instantly has the other, opposite spin. Bob’s particle will always have the opposite spin to Alice’, no matter how far apart the particles are. Somehow, they communicate faster than light and determine their outputs. This has actually been proven experimentally to be true, over and over. Einstein didn’t like it – he called it “spooky action at a distance” and declared that “God does not play dice with the universe”.

We now know that it is true, and the hypothetical medium through which the p[articles communicate is called the Bell Continuum, and it is the place in the “Star Trek: Next Generation” series that “Q” lived.

Here’s the part that blew my mind. Distance is one thing, but we see time as being something else, something fixed in the past and changeable in the future. However, let’s suppose I look up at the night sky. A human eye is quite capable of seeing a single quantum of light energy. The impact of the quanta on my retina in effect measures the quantum attributes (numbers) of the quantum, and transmits that information to my brain where the observer lurks.

That pins down the quantum of light energy. Any other quanta with which it is entangled have to “decide” their own states as a result. Now let’s suppose that these quanta all came from a quasar stellar explosion billion of years ago, and that some of the entangled quanta have already interacted with other matter elsewhere in the galaxy (which is very likely). By capturing and observing the quantum here on Earth in 2009, I am affecting (changing?) the past all the way back to the creation of the entangled particles.

When we look at things, we are not only creating them here in the here and now (by collapsing their uncertainty waves), but we are also creating the past, and our present is being changed by people in the future as I write this.

Mouth slackly hanging open ………