Quantum mind with a cat in a locked steel chamber, wherein the cat's life or death depended on the state of a radioactive atom, whether it had decayed and emitted radiation or not. According to Schrödinger, the Copenhagen interpretation implies that "the cat remains both alive and dead" until the state has been observed. Schrödinger did not wish to promote the idea of dead-and-alive cats as a serious possibility; on the contrary, he intended the example to illustrate the absurdity of the existing view of quantum mechanics. However, since Schrödinger's time, other interpretations of the mathematics of quantum mechanics have been advanced
Symmetry in quantum mechanics act on any four vector A = ("A", "A", "A", "A") and mix the time-like and the space-like components, according to: In relativistic quantum mechanics, wavefunctions are no longer single-component scalar fields, but now 2(2"s" + 1) component spinor fields, where "s" is the spin of the particle. The transformations of these functions in spacetime are given below. Under a proper orthochronous Lorentz transformation in Minkowski space, all one-particle quantum states locally transform under some representation of the Lorentz group: where is a finite-dimensional representation, in other words a dimensional square matrix, and is thought of as a column vector