1 post tagged “quantum physics”
Margaret: Daddy, what is a "might-have-been"?
Dearth: A "might-have-been"? They're ghosts, Margaret! I daresay I "might-have-been" a great swell of a painter, instead of just this uncommonly happy nobody - or again I might have been a worthless idle waster of a fellow.
Margaret: You?
Dearth: Who knows? Some little kink in me might have set off on the wrong road. And that poor soul I might so easily have been might have had no Margaret. I'm sorry for him.
Margaret: And so am I! The poor old daddy, wondering the world without me.
Dearth: There are other "might-have-beens" - lovely ones, but intangible. Shades, Margaret, made of sad folks' thoughts.
- Dear Brutus, Act II, by J. M. Barrie.
Is it possible that this author of Peter Pan also invisioned, in this lesser-known work first performed in 1917, the Many Worlds Interpretation of quantum physics?
What follows is an extreme simplification of the theory, and is about all I understand of it, not being a physicist myself, and therefore might be wrong.
Elementary particles behave in a random fashion. How they behave is, by some degree, determined by chance. For instance, there may be a 10% chance that a particular neutron will decay within a particular second, and a 90% chance that it won't.
The problem this presents for physicists is that in physics thing's aren't really random. For instance, if you were to toss a coin, you might think that there is a 50% chance that the coin will be heads-up when it stops. The truth is that chance is illusory, in this and in every case. The illusion of chance is created by the fact that we, as humans, couldn't possibly know, measure, or calculate all of the variables that will decide whether the coin will land heads or tails. If we could know everything about the coin, the pressure being applied to it by the person flipping it, the weight variable caused on the two sides by the impressions on the coin, etc., and knew how all of those factors would weigh on the outcome and how to calculate it, it would be theoretically possible to predict with 100% accuracy which way the coin would land every time. In other words, it only looks random because we don't know all the facts.
But elementary particles are just that - elementary. They consist of nothing smaller but pure energy, which has no further characteristics. So, if there is a 10% chance that the neutron will decay, why is it that sometimes it will decay, and sometimes it won't? Is it true, then, that some parts of the universe are left to pure chance, while everything else has a root cause? The concept lacks aesthetic appeal to physicists, and is one of the reasons why Albert Einstein didn't like quantum theory, stating famously that "God doesn't play dice."
So enter the Many Worlds Interpretation. The Many Worlds Interpretation posits that every time there is a chance that a quantum particle may behave one way or another, the universe splits off into two parallel versions of itself, one in which the neutron decayed, and one in which it didn't. Since these quantum variations are happening around us all that time, that means that based on the theory, there are infinite numbers of parallel universes branching out all the time.
We can think of MWI as positing that universes are "created" every time an elementary particle could randomly do one thing or another, but of course that would require unfathomable amounts of energy to come out of nowhere all of the time. Rather, these universes exist already, and we are reaching them by following various paths along the probability matrices of the quantum particles.
It's important to note that proponents of MWI don't just like the theory for its aesthetics. It also solves a number of paradoxes famous to quantum physics, such as the Schrödinger's Cat paradox. In that thought experiment, a device is set up to kill a cat in a box if a radioactive atom decays. There is a quantum probability that the atom may or may not decay, and we won't know which it was until we look in the box. So, until we look in the box, is the cat alive, dead, or some bizarre, mixture of the two, since we don't know yet what the result of the cosmic dice shoot was? By applying the Many Worlds theory to the problem, the simple answer is that in one universe the cat is alive, and in the other universe the cat is dead. Looking in the box simply confirms to us which universe we're in.
For science fiction fans such as myself, where MWI becomes interesting is when it is extrapolated to the macro level. The decaying of a single atom, with the exception of the poor cat, has little effect on whether any of us live or die, or make it to work on time, or even win the Lotto. Taken in the agregate, however, quantum effects make all the difference in the world, literally. In other words, every event that happens that could have gone one way or another, came out the way that it did because of a general drift in the quantum probabilities that ultimately effected that event.
So, if I notice that the light has turned red too late and slam on the brakes, there are a myriad of factors that will determine whether I slam into another car trying to cross the intersection or whether I slide on through, unharmed. Ultimately, those factors boil down to quantum probabilities, and so in some universes I slid on through the intersection. In this one, I T-boned someone. In fact, anything that is possible, no matter how improbable, happens in at least some of the universes.
Dear Brutus explores these ideas, realizing that our choices lay out ahead of us like a myriad branching paths. We think that we are making a choice, but in fact universes exist in which we take each of these paths, though some universes are more prevalent than others. The universe we are in now is the result of paths taken, and paths not taken are lost to us forever.
Dearth: Three things they say come not back to men nor women--the spoken word, the past life and the neglected opportunity.
- Act I
Those of you who have read the Golden Compass recently will recognize the theory explained nicely there, as well. In Dear Brutus, the characters get to visit those "might-have-been" worlds, shades made of sad folks thoughts, lovely, and intangible.
