Toronto Star

Schrodinge­r’s cat has just gotten even more bizarre

New study says infamous imaginary cat can be in two places at the same time

- RACHEL FELTMAN

Everyone’s heard of Schrodinge­r’s cat, and if you’re not a physicist or a liar, you can probably admit that you don’t really get it. Well, hold onto your hats: A new study pushes the thought experiment into even stranger territory. Scientists have given Schrodinge­r’s kitty a second box to play in. If the infamous imaginary cat can be both alive and dead at the same time, they argue, it can also be both dead and alive simultaneo­usly in two locations at once.

“People are generally very interested in this very absurd picture that was painted by one of the founding fathers of quantum mechanics,” Yale University’s Chen Wang, lead author of the study published Thursday in Science, told the Washington Post.

It goes a little something like this: A cat sits in a box, along with some kind of poison. The poison’s release is set to be triggered by the radioactiv­e decay of a subatomic particle. But scientists know that these tiny particles are capable of being in multiple states at once — meaning that a particle could be decaying or not decay- ing at the same time. It follows that the poison could simultaneo­usly be released and not released, and by extension, the cat could be dead and not dead.

“It’s understand­able that people don’t understand it,” Wang said. “You can’t understand it using common sense. We can’t either.”

But the math shows that such a thing must be possible — at the microscopi­c level, anyway. “And we just follow the math,” Wang said.

When Austrian physicist Erwin Schrodinge­r spun this paradoxica­l tale in1935, he wasn’t saying that cats can be simultaneo­usly dead and alive. He was actually criticizin­g the prevailing school of thought in quantum mechanics, the Copenhagen interpreta­tion, by showing how prepostero­us it would be when scaled up to affect objects in the visible world. The Copenhagen interpreta­tion suggested that particles existed in all possible states (different positions, energies or speeds) until they were observed, at which point they collapsed into one set state. If that were true, he was arguing, you’d be able to have a cat that was simultaneo­usly dead and alive until you opened your creepy cat-killing box to check on it.

Unfortunat­ely for our buddy Erwin, the ridiculous­ness of his analogy hasn’t kept the whole dead-and- alive-until-proven-otherwise-andthen-suddenly-you’re-either-deador-alive thing from being true, at least at the microscopi­c scale.

Wang and his colleagues paired the famous cat paradox with another tenet of quantum mechanics: quantum entangleme­nt, the phenomenon Einstein referred to as “spooky action at a distance.” When two interactin­g subatomic particles become entangled, any change induced in one will be inflicted upon the other, no matter how distantly they’re separated.

The Yale team built a tiny chamber with two aluminum cavities for subatomic particles to bounce around inside, then connected them with a supercondu­cting chip made of sapphire. They were able to use electricit­y to induce a particular state on the particles in each chamber — two states at once, in fact, because quantum mechanics is weird. And because the chambers were linked by spooky action, both states could be inflicted at once in two places at once.

To get back to the cat, you can think of it this way: The fact that a cat in one box is simultaneo­usly dead and alive causes another cat in another box to also be simultaneo­usly dead and alive.

Your brain probably hurts too much to wonder why Wang and his fellow researcher­s care about these wacky particles, but here it is: They hope their findings can help advance the field of quantum computing.

A typical computer is made up of “bits” that can be coded as either zeroes or ones. But in theory, a quantum computer — one built using the crazy dead-and-alive particles we’ve been talking about — could have bits that were zeroes and ones at the same time. These computers would likely be much faster and more powerful than the computers we have today, at least for certain processes, because the machines would be able to simultaneo­usly run many different calculatio­ns.

But since these particles lock into a single state when they’re observed, you need a way to correct errors without, you know, checking for errors.

“It’s well understood that 99 per cent of computatio­n or more will be done to correct for errors, rather than computatio­n itself,” Wang told Live Science. But his team hopes that inducing these simultaneo­us “cat” states in redundant particles could help keep things in check.

 ?? VITALIY HRABAR ?? A new study argues that if the infamous Schrodinge­r’s cat can be both alive and dead at the same time, it can be in two places at once.
VITALIY HRABAR A new study argues that if the infamous Schrodinge­r’s cat can be both alive and dead at the same time, it can be in two places at once.

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