Müller and Masanes

1. The state of a composite system is characterized by the statistics of measurements on the individual components.

2. All systems that effectively carry the same amount of information have equivalent state spaces.

3. Every pure state of a system can be transformed into every other by continuous reversible time evolution.

4. In systems that carry one bit of information, all measurements which give non-negative probabilities are allowed by the theory.

arXiv

Postulates for Quantum Mechanics