Vendredi 24 mars 2017
Causality without events
Michal ECKSTEIN (Uniwersytet Jagiellonski, Krakow)
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. It is usually believed that the quantum nature of spacetime at small scales induces the breakdown of causality, although there is no empirical evidence that would support such a view. In my talk, I will argue that one can have a rigid causal structure even in a `quantum spacetime’ without the local events. To this end I will draw from the mathematical richness of noncommutative geometry à la Connes and an operational viewpoint on physics. I will illustrate the general concept with an `almost commutative’ toy-model and discuss the potential empirical consequences.