Schrödinger's cat Schrödinger's cat Schrödinger's cat is a thought experiment, sometimes described as a paradox, devised by Austrian physicist Erwin Schrödinger in 1935. It illustrates what he saw as the problem of the Copenhagen interpretation of quantum mechanics applied to everyday objects. The scenario presents a cat that may be simultaneously both alive and dead, a state known as a quantum superposition, as a result of being linked to a random subatomic event that may or may not occur. The thought experiment is also often featured in theoretical discussions of the interpretations of quantum mechanics. Schrödinger coined the term "Verschränkung" (entanglement) in
Popper's experiment Popper's experiment based on this impossibility of superluminal communication in quantum mechanics. Use of quantum correlations for faster-than-light communication is thought to be flawed because of the no-communication theorem in quantum mechanics. However the theorem is not applicable to this experiment. In this experiment, the "sender" tries to signal 0 and 1 by narrowing the slit, or widening it, thus changing the probability distribution among the "receiver's" detectors. If the no-communication theorem were applicable, then no matter if the sender widens the slit or narrows it, the receiver should see the same probability distribution among his detectors. This is true,