Schrödinger's Cat

CORE DEFINITION

Schrödinger's cat is a thought experiment proposed by Austrian physicist Erwin Schrödinger in 1935. Through this thought experiment, Schrödinger pointed out the problems that arise when applying the Copenhagen interpretation of quantum mechanics to macroscopic objects, and its contradiction with physical common sense. In this thought experiment, due to the random nature of prior events, the cat would be in a superposition of being alive and dead. According to decoherence theory, the cat cannot remain in a superposition of alive and dead forever; due to environmental influences, decoherence would quickly occur, and the cat would instead be in a classical statistical state of being either alive or dead. Therefore, in general, it is absolutely impossible to observe a superposition of alive and dead. To date, physicists can only carefully prepare superposition states of some mesoscopic objects. Although Schrödinger's cat is a thought experiment, similar principles have been applied in practical fields. In theoretical discussions of quantum mechanics interpretations, Schrödinger's cat is also often raised as a touchstone.