Środowiskowe Seminarium z Informacji i Technologii Kwantowych

Einstein's causality is one of the fundamental principles underlying modern physical theories. Whereas it is readily implemented in classical physics founded on Lorentzian geometry, its status in quantum theory has long been controversial. Recently, the idea that the causal order of events can be superposed -- `quantum causality' -- became popular. During my talk I will advocate the viewpoint on causality as a rigid, geometrical, property of spacetime. Basing on a joint work with Nicolas Franco (Namur) and Tomasz Miller (PW), I will demonstrate that the causal structure can be rigorously defined also beyond classical physics. To this end, however, one needs to adjust the very notion of geometry and adopt an operational viewpoint on spacetime. I will illustrate the general concepts with simple examples from (relativistic) quantum mechanics.