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) A particularly simple case arises when formula_1 is a projection, and thus has only the eigenvalues 0 and 1. This physically corresponds to a "yes-no" type of experiment. In this case, the expectation value is the probability that the experiment results in "1", and it can be computed as (3) formula_24. In quantum theory, also operators with non-discrete spectrum are in use, such as the position operator formula_25 in quantum mechanics. This operator does not have eigenvalues, but has a completely continuous spectrum. In this case, the vector formula_11 can be written as a complex-valued function formula_27 on the spectrum