# Who did enunciate each postulate of modern Quantum Mechanics

Nonrelativistic Quantum Mechanics (QM) relies in a number of postulates and although some authors may disagree about the exact set, there are a few which are quite indisputable:

1. States are represented by vectors in a Hilbert space.
2. Observables are represented by Hermitian operators acting on the Hilbert space.
3. If the system is in state $|\psi\rangle$, then the measurement of the observable $A$ yields one of the eigenvalue of the operator associated to $A$.
4. (Born Postulate) The probability of measuring $A$ and obtaining $a$, given that the system is in the state $|\psi\rangle$, is $|\langle a|\psi\rangle |^2$. After the measurement, the system is found to be in state $|a\rangle$.
5. The state vector of the system obeys the Schrodinger equation.

Who did formulate the first three of these principles (or any other you may regard as fundamental) as fundamental postulates of QM?