June 1, 2004

How many universes am I holding up ?

One thing leads to another. I'm back pondering the mysteries of Quantum Mechanics. Someone said to me, over a cup of astro tea, "what's new ?", to which I replied, "quantum computing".

To my surprise, my eminent colleague was unaware that such a thing existed, conceptually or otherwise. Before long we were debating various interpretations of the double-slit experiment.

As I understand it, the fact that a single particle can appear to be in two places at once has profound implications regarding the structure of reality and can be explained in several ways. Here's two :

A physical system remains in a superposed state of all possibilities until it interacts with an observer at which point it collapses to one of these possibilities. The particle goes through both slits until observed, at which point the act of observation forces it to go be in just one place, to pass through one or the other slits.


Whenever something is confronted with a choice the universe splits into many universes, so that each possibility exists in a different universe.
The particle has two choices - to pass through the left slit or the right slit. At this point the universe splits into two universes. In one the particle goes through the left slit, in the other it goes through the right slit.

At the moment, given the information I posses, I subscribe to the latter, the "many worlds interpretation". It can be a comfort. For example:

Yesterday Marcia and I were in the Tate Gallery (the old one as opposed to Tate Modern). We were looking at a large vitrine in which there were a number of very beautiful butterflies. They appeared to be dying. Seeing as how a lot of other art works in the same space were composed of dead flesh there is no reason to suppose they weren't. Behind me on the floor was a very large black banana (a sculpture). I heard a voice in my head, an old friend, Joe, enticing us to pick it up. "Hey, Finer (some public school throwback, he'd use my surname while trying to incite mischief) . . . you and Marcie, pick up the banana. Free the butterflies".

The choice was whether to pick up the giant black banana and then smash it into the large vitrine, thus setting free the butterflies within, or not. We didn't, but I wish that we had. It is a comfort to know that there now exists a universe in which we did wield the banana, with the desired effect.

Posted by Jem Finer at June 1, 2004 3:38 PM