Quantum mind by physicists, some of which regard the "alive and dead" cat superposition as quite real. Schrödinger's famous thought experiment poses the question, ""when" does a quantum system stop existing as a superposition of states and become one or the other?" In the same way, it is possible to ask whether the brain's act of making a decision is analogous to having a superposition of states of two decision outcomes, so that making a decision means "opening the box" to reduce the brain from a combination of states to one state. But even Schrödinger didn't think this really happened to the
Expectation value (quantum mechanics) general case, its spectrum will neither be entirely discrete nor entirely continuous. Still, one can write formula_1 in a spectral decomposition, with a projector-valued measure formula_30. For the expectation value of formula_1 in a pure state formula_48, this means which may be seen as a common generalization of formulas (2) and (4) above. In non-relativistic theories of finitely many particles (quantum mechanics, in the strict sense), the states considered are generally normal. However, in other areas of quantum theory, also non-normal states are in use: They appear, for example. in the form of KMS states in quantum statistical mechanics of