Larsen's theorem

Larsen's theorem states that in quantum physics, the maximum amount of information that can be extracted from a quantum system using a measurement is limited by the system's own intrinsic properties. Specifically, it clarifies that no measurement, no matter how advanced, can surpass this maximum without disturbing the system. Essentially, it sets a theoretical boundary on how much you can learn about a quantum system without altering it, highlighting the fundamental limits imposed by quantum mechanics on information retrieval and measurement processes.