Monday, November 19, 2012

Spooky Action at a Distance (Quantum Entanglement)

So what is this thing called quantum entanglement? Since it’s the premise of my YA thriller, Entanglement, I figure it’s time to shed some light on this eerie phenomenon. In Entanglement, every human is born with a soul mate—their half, as it’s called in the book.

Picture this: 

The moment you’re born, halfway around the world someone else is born at the exact same time. You and this person share a subtle telepathic connection that appears to travel faster than light. If one of you dies, the other feels it instantly…and follows shortly. The two of you are soul mates. An entangled pair.

As it turns out, this is not far from the truth. In reality, subatomic particles can—and do—become entangled all the time. Theoretically, humans could too. Entanglement was discovered around 1935, to which Erwin Schrodinger commented, “I would not call [it] one but rather the characteristic trait of quantum mechanics.” Albert Einstein didn’t believe it and called it “spooky action at a distance.”

Here’s how it works

We’ll start by shining a laser at a crystal, so it splits into two different beams. It might look something like this:

Now let’s go down to the subatomic level. Imagine a single photon hitting the crystal and splitting into two different photons. Just like the light. Now imagine one of these photons came out spinning like a top. Because of conservation of angular momentum, the other photon would have to be spinning in the opposite direction. Make sense? Their total angular momentum must add up to zero.

Now let’s let these photons travel a few billion miles away from each other, and let’s take another look at them. They’re still spinning in the exact opposite directions, because nothing has interfered with them.
But now we have a problem. Photons are so small that the laws of physics get kind of hazy at their scale, and it’s really more accurate to say they’re spinning in all directions at once. They haven’t really decided yet which direction they’re spinning, just that they’re opposite. Each one is like a coin that is still flipping in the air. It’s both heads and tails at the same time. But that’s no good.

So we reach in and stop the photon from spinning. It’s like we’re slapping the coin against our palm to freeze it in heads or tails (I’m using heads and tails now to describe spinning one direction versus the other). But this is where it gets really sticky.

Remember that other photon? How it had the opposite spin? Well it still does. A second ago, both photons were spinning in all directions at once. But now that we’ve stopped one photon at tails, the other one—even though it’s a billion miles away—instantaneously takes on heads.

Somehow, the one photon communicated its “collapsed” state to its other half faster than light, across any distance, and through whatever obstacles, thus violating relativity. It’s as if they were connected at a more fundamental level, through a hole in space, perhaps, or via another dimension. That's where the term entangled comes from.

No one yet has come up with a good explanation.

Creepy, huh?

If you want to see it in humans, check out Entanglement on Amazon, or read the first 3 chapters for free. And if you enjoyed reading this, hover your mouse over the “share” button below, and you’ll see a few options for sharing this blog post with friends. Share it with a few friends and help me get the word out!

Thanks for reading!
Dan Rix, author of Entanglement.

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