926 citations · 5.8k across the 51 of their papers we have counts for
51 papers
A de Finetti theorem for quantum causal structures
Fabio Costa, Jonathan Barrett, Sally Shrapnel
What does it mean for a causal structure to be `unknown'? Can we even talk about `repetitions' of an experiment without prior knowledge of causal relations? And under what conditio…
Quantum influences and event relativity
Nick Ormrod, Jonathan Barrett
We develop a new interpretation of quantum theory by combining insights from extended Wigner's friend scenarios and quantum causal modelling. In this interpretation, which synthesi…
Which theories have a measurement problem?
Nick Ormrod, V. Vilasini, Jonathan Barrett
It is shown that any theory that has certain properties has a measurement problem, in the sense that it makes predictions that are incompatible with measurement outcomes being abso…
Device-independent certification of indefinite causal order in the quantum switch
Tein van der Lugt, Jonathan Barrett, Giulio Chiribella
Quantum theory is compatible with scenarios in which the order of operations is indefinite. Experimental investigations of such scenarios, all of which have been based on a process…
Consistent circuits for indefinite causal order
Augustin Vanrietvelde, Nick Ormrod, Hlér Kristjánsson +1
Over the past decade, a number of quantum processes have been proposed which are logically consistent, yet feature a cyclic causal structure. However, there is no general formal me…
Causal structure in the presence of sectorial constraints, with application to the quantum switch
Nick Ormrod, Augustin Vanrietvelde, Jonathan Barrett
Existing work on quantum causal structure assumes that one can perform arbitrary operations on the systems of interest. But this condition is often not met. Here, we extend the fra…