Quantum Mechanics at Forty Thousand Feet
"So chaps, what is a Schrodinger's cat?"
Several clever responses simultaneously spring to Douglas and Martin's minds (Douglas's more so, perhaps, than Martin's), but neither of them manages to articulate anything before Arthur continues with his good-natured queries.
"How does it work, then, being alive and then not alive and then alive again? That sounds fun, actually; if it could talk, it could tell us what it was like being dead after it comes back to life!"
Douglas snaps into flight mode, which is the mode in which he gives long-winded and frankly impressive expert talks on things Arthur cannot possibly hope to understand. He finds himself activating it all too often nonetheless.
"Arthur, one, cats cannot talk."
"Oh, right, I knew that. But sometimes it just seems like they can—"
"Two, Schrodinger's cat is not a real cat. It is a paradoxical reductio ad absurdum used as an example of how the superposition of two quantum states cannot function at—"
"Douglas, Arthur speaks English, not advanced physics," Martin intercedes.
"Go on, then, Hawking, you explain it to him. I presume you know the general setup."
"Of course, it's pretty much pop culture these days," Martin says dismissively. "All right, Arthur, here's how it works: you have a cat in a box—"
"But I don't have a cat. I wish I had one."
"No, no, you don't have a cat. Schrodinger had a cat."
"Hence its designation as Schrodinger's cat," Douglas says unnecessarily.
"Yes, Douglas, thank you. Ok. So, Schrodinger, who by the way was a scientist who lived about a hundred years ago," he adds quickly because Arthur looks on the verge of another querying outburst, "he thought, what if there was a cat in a box? And in this box, there was a Geiger counter (that's a machine that measures radiation), and then there is a source of radiation. Like a uranium rod."
Arthur looks confused even at this early stage, and Martin almost gives up, but then Arthur's expression brightens, and he says as if very enlightened, "Oh, uranium! They have that in those factory places where everything is marked with the yellow sign that looks like a fan! I know about that."
"Trefoil," Douglas pronounces.
Martin and Arthur look at him, equally puzzled.
"That's what the yellow fan is called, trefoil. It's the universal symbol for radiation. It's called that because it's from the Latin trifolium, which means three leaves, and it looks like three leaves. Not because it has anything to do with trees or foil."
Martin rolls his eyes at the impromptu but not unexpected dead languages lecture; Arthur is clearly still several minutes behind.
"Go on, Martin."
"Right. So, we've got the cat in the box with the Geiger counter and the uranium. The box is closed so you can't see anything inside. Now, at any given moment—"
"Wait," Arthur interrupts. "Are there holes in the box so the cat can breathe? Because if it doesn't, then the cat will be more likely to die because it can't breathe."
"Arthur," Martin says impatiently. "Just, bear with me. All right? Assume the cat doesn't need to breathe, or eat, or sleep, or do anything that cats normally do. It's an immortal cat."
Douglas sees an immediate problem with this statement, but holds his tongue as Martin waits for Arthur to give a nod of dubiously suspended belief. Having received the go-ahead, Martin continues. "So, at any given moment, there is either radioactive decay in the uranium, or there isn't."
"What's decay?"
Douglas senses Martin may need a little help with the science here and cuts in. "Radioactive decay is the process by which the nuclei of volatile atoms split, releasing alpha and beta particles or gamma rays."
"Oh, alpha and beta like the African hunting dogs? Do they have amigo particles too?"
At this point, Martin thinks he may have an aneurysm, except that his usual fare, low in sodium and glucose and, well, low in everything, really, comes with the benefit of decreased hypertension. He can still get a headache from Arthur's nonsense if it goes on for much longer, though.
"For the purposes of your understanding, Arthur, radioactive decay is something invisible that will kill the cat. So, while the box is closed, you don't know if the cat is dead or alive. It could be dead and it could be alive. But once you open the box up and look inside, it can only be one of the two: dead or alive. Therefore, the situation is a paradox, because while the box is closed, there are two possible states for the cat to be in, but when the box is opened, there is only one. They can't coexist. Do you see?"
Arthur frowns deeply, ponders for a moment, and then nods. "Yeah, I do see."
Martin sucks in a skeptical breath. "Are you sure? It's a complex concept—"
"Absolutely existential," Douglas adds, just for something to say.
"—so obviously, you needn't understand it completely—"
"No, Skip, I understand completely. When you can't see the cat, you don't know if it's dead or alive, so it might be both. When you can see the cat, you know which one it is. But there's still something I don't understand."
Wait for it, Douglas thinks, you knew this would come up…
"Wasn't the cat immortal?"
Indeed.
"And, why would Schrodinger put his cat in a box where it might die? He sounds like an awful chap!"
Martin looks at Douglas. It is not a happy look. Fortunately, the time has come for feeding the animals, and Arthur is requisitioned back into the main cabin. Martin and Douglas silently thank the sky god, whose name might just happen to be Carolyn Knapp-Shappey.
"Chaps, I've just remembered! We had a Schrodinger's cat once!" Arthur bursts back into the flight deck half an hour later, excited by his own revelation. Martin and Douglas are hardly fazed.
"When did this happen?" Martin asks.
"It was a while ago, when we were flying stuff to Abu Dhabi. The client's cat in the hold, remember? We didn't know if it was dead or alive, and we couldn't check on it. So it was both until we opened the hold at Paris and it was alive!"
"Ah," Douglas says. "Good point, Arthur. We unwittingly carried out Schrodinger's vision in our very own cargo hold. Imagine the press if they knew what we'd done for science."
"Yes. Although that cat was awful; it scratched me to shreds. I think Schrodinger would have been right to put it in a radioactive box and let it die. Do you think maybe the client was related to Schrodinger?"
"No, Arthur," Martin says. "I can be reasonably sure the client did not volunteer his own cat for reenacting his ancestor's experiment under the adept supervision of three aircraft-crew-turned-researchers."
"Aw, that's too bad. Do you think the experiment would work with dogs, too? We could use Snoopadoop! I bet she'll love it. Plus it'll be easier to put her in the hold, 'cause she won't scratch me."
"Arthur…you may want to check with your mother before you do that," Douglas cautions. "After all, you don't want to risk Snoopadoop accidentally dying in the hold."
"…right," Arthur remembers the possibly deadly parameters of the experiment. "Maybe not such a great idea."