Project title: Causal models and indefinite causal order in Quantum Theory
Supervisors: Florian Mintert (Imperial College), Bob Coecke (Oxford) and Giulio Chiribella (Oxford)
The aim of this project is to work towards a better understanding of the causal structures allowed by Quantum Theory. Such an understanding would be of interest for technological applications in quantum communication and quantum computing; moreover, it could also shed light on the causal structures which may arise in a theory of quantum gravity. This project currently focuses on the study of quantum causal models, which give a precise meaning to the notion of a definite causal structure existing between some quantum systems; and on the closely related study of indefinite causal order, which takes a step further and investigates the possibility of scenarios allowing for an indefinite causal structure, that is, a causal structure which itself features quantum phenomena. In the past few years, it has been proven that the physical realisation of such an indefinite causal order would entail a number of computational and communicational advantages over what is achievable with quantum protocols featuring a definite causal order.