Why We Don't See the Schrödinger's Cat State? Typeset Using Revt E X

Schrödinger’s cat puzzle is resolved. The reason why we do not see a macroscopic superposition of states is cleared in the light of Everett’s formulation of quantum mechanics. 03.65.Bz Typeset using REVTEX 1 Schrödinger argued [1,2] incompleteness of the Copenhagen interpretation of quantum mechanics by showing a paradoxical thought experiment known as “Schrödinger’s cat”: A cat is placed in a sealed box with a device which releases a fatal dose of cyanide if a radioactive decay is detected. After a while, a human opens the box to see if the cat is alive or dead. According to the Copenhagen interpretation, the cat was neither alive nor dead until the box was opened, and when the human peeked in the box the wavefunction of the cat collapsed into one of the two alternatives (otherwise the human might be able to see a live cat after having seen a dead cat!). The paradox is that the cat presumably knew if it was alive before the box was opened, that is, the cat must have been either alive or dead before the human opened the box. As long as we adhere to the Copenhagen interpretation, the paradox will not be resolved scientifically, because it provides no means to analyze the whole system including the observer system. In the Copenhagen interpretation, the measurement process cannot be described by any equation, but instead must be implemented by hand. Everett proposed a new formulation of quantum mechanics [3], in which the collapsing process of the wavefunction is ascribed to a branching process of the observer state. That is, the wavefunction of the cat never collapses into one of the two alternatives but instead the wavefunction of the human branches into two states, each of which being correlated to one of the alternatives. One then may ask why the observer state always correlates to the live-cat state and the dead-cat state, rather than the other possible superposed alternatives, or to the “Schrödinger’s cat state”. Recent studies [4–13] have been focused on this issue and people have tried to show how the preferred basis can be selected through the process of interaction with the environment. In this Letter, I will give an answer to this puzzle from a different point of view. In order to understand what it means, we need to refine the formulation. The answer will then follow as a natural consequence. In Everett’s formulation of quantum mechanics, we do not interpret the squared modulus of the wavefunction as the probability, but interpret it as a measure which satisfies the 2 following property: When a subset of a superposition ∑ iXi|ξ 〉 is described as a single element Y |η〉;