[AN] Hans Maassen: Continuous observation of quantum systems

28 May 2024 16:00 till 17:00 - Location: EEMCS Lecture Hall Chip | Add to my calendar

Stationary observation of a small quantum system, such as an atom or molecule, can be done by detecting the photons which it emits, or by measuring the electromagnetic field waves that it sends out.
This physical fact has a mathematical counterpart: a certain kind of "observation records" consist of a point process plus a diffusive process, close to a Brownian motion. A theorem to this effect was proved by Alexander Holevo in the 1980's, using functional analytic techniques. It resembles the classical Lévy-Khinchin formula for infinitely divisible probability distributions. And indeed, steady observation records are infinitely divisible in an interesting sense. In this talk I present Holevo's Theorem in a new way, and sketch a proof based on weak convergence of measures.