Thursday, October 25, 2018, 16:00
WBGB/019
Caslav Brukner, Vienna University
Abstract:
One of the most deeply rooted concepts in science is causality: the idea
that events in the present are caused by events in the past and, in
turn, act as causes for what happens in the future. If an event A is a
cause of an effect B, then B cannot be a cause of A. The possible
interplay between quantum theory and general relativity may, however,
require superseding such a paradigm. I will review the framework of
"process matrices", which allows describing "superpositions of causal
order", where one cannot say that A is before or after B. The framework
reduces to the standard quantum formalism whenever the causal order is
fixed. I will then show how one could realize indefinite causal
structures in the gravitational field of a massive object in a spatial
superposition.