Schrödinger
Americannoun
noun
Usage
What is Schrödinger's cat experiment? Schrödinger’s cat is a famous physics thought experiment, which presents a paradox in which a cat in a box is somehow simultaneously both alive and dead.
Closer Look
Schrödinger's cat is a thought experiment proposed by the physicist and philosopher Erwin Schrödinger. It shows how quantum-mechanical indeterminacy at a microscopic level can cause indeterminacy at a macroscopic level. The indeterminacy can be resolved by observation but entails a paradox. Schrödinger would have us imagine a cat inside a closed box with a tiny bit of a radioactive substance and an apparatus consisting of a Geiger counter, hammer, and flask of cyanide. Over the course of an hour, there is a chance that the radioactive substance might emit an alpha particle, and an equal chance that it might not. If an alpha particle is emitted and hits the Geiger counter, a relay is set in motion whereby the hammer shatters the flask, releasing the gas and killing the cat. Thus, after an hour, there is equal probability of the cat being alive or dead, and an observer can open the box and see which state the cat is in. But until the observation is made, the two possible states, which are mutually exclusive, coexist. In quantum-mechanical terms they are in a condition of superposition. The act of observation changes that, and one state becomes established to the exclusion of the other. In other words, without being observed, the cat does not exist in a particular state at all. It is neither alive nor dead, or it is both alive and dead, depending on how you want to look at it. This thought experiment provides an extreme case of the condition in which small-scale objects always exist. Under the laws of quantum mechanics, electrons, photons, and all other particles are each in a number of superposed states that interact with each other, forming interference patterns, and giving rise to an overall behavior that often seems wavelike. But a measurement made to determine the state that the particle is in destroys the interference patterns and gives rise to different behavior that seems more like that of tiny particles; hence the phenomenon of wave-particle duality. Whether the cat in the box can also be considered an observer in quantum mechanics currently remains unclear.
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The researchers also found that a version of the Schrödinger equation, the fundamental equation of quantum mechanics, can be expressed using entropic time.
From Science Daily ● Jul. 9, 2026
Physicist Erwin Schrödinger famously illustrated the mystery with his thought experiment involving a cat that is simultaneously alive and dead until observed.
From Science Daily ● Jul. 8, 2026
I used words like qubit, superposition, Schrödinger, and cat, some of them perhaps even correctly.
From Barron's ● May 29, 2026
Physicists describe these conditions as Schrödinger cat states, referencing Austrian physicist Erwin Schrödinger's famous thought experiment involving a cat that is simultaneously dead and alive until observed.
From Science Daily ● May 11, 2026
Schrödinger imagined a chemical with multiple chemical bonds stretching out along the length of the “chromosome fiber.”
From "The Gene" by Siddhartha Mukherjee
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
