Physicists Can Finally Peek at Schrödinger’s Cat Without Killing It Forever


There may be a way of sneaking a peak at Schrödinger’s cat — the famous feline-based thought experiment that describes the mysterious behavior of subatomic particles — without permanently killing the (hypothetical) animal.

Dana Najjar | SPACE.com

The unlucky, imaginary cat is simultaneously alive and dead inside a box, or exists in a superposition of „dead“ and „alive“ states, just as subatomic particles exist in a superposition of many states at once. But looking inside the box changes the state of the cat, which then becomes either alive or dead. 

Now, however, a study published Oct. 1 in the New Journal of Physics describes a way to potentially peek at the cat without forcing it to live or die. In doing so, it advances scientists‘ understanding of one of the most fundamental paradoxes in physics. 

In our ordinary, large-scale world, looking at an object doesn’t seem to change it. But zoom in enough, and that’s not the case.

„We normally think the price we pay for looking is nothing,“ said study lead author Holger F. Hofmann, associate professor of physics at Hiroshima University in Japan. „That’s not correct. In order to look, you have to have light, and light changes the object.“ That’s because even a single photon of light transfers energy away from or to the object you’re viewing. 

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