Quantum systems can behave in a manner that is fundamentally different from classical systems, and this enables quantum advantages in a wide range of tasks from cryptography to computation. Many of these advantages stem from the fact that causality plays a significantly different role in quantum theory than in classical physics.

The purpose of the project is to investigate causality in quantum theory, both from a foundational perspective and with applications to quantum information processing. The foundational part will develop a theory of quantum causal networks, which will provide a method for describing quantum systems that have definite causal relationships between them.

The aim is to determine quantitatively the non-classical behaviours that such quantum systems can exhibit. The applications part will apply this theory to novel protocols for quantum communication and cryptography, where an understanding of more involved causal structures is essential.


  • Jonathan Barrett, Department of Computer Science, University of Oxford
  • Stefano Pironio, Quantum Information Laboratory, Université libre de Bruxelles

Thanks to the Foundation’s support, two researchers have been hired to work on this project: Dr Ravishankar Ramanathan at the ULB and Dr Ognyan Oreshkov at the University of Oxford.