One of the most basic notions in physics is the partitioning of a system into subsystems and
the study of correlations among its parts. In this Letter, we explore this notion in the context of …

A reconstruction of quantum theory refers to both a mathematical and a conceptual
paradigm that allows one to derive the usual formulation of quantum theory from a set of …

It is useful to have a criterion for when the predictions of an operational theory should be
considered classically explainable. Here we take the criterion to be that the theory admits of …

One of the most striking features of quantum theory is the existence of entangled states,
responsible for Einstein's so called “spooky action at a distance.” These states emerge from …

This paper is a 'spiritual child'of the 2005 lecture notes Kindergarten Quantum Mechanics
Coecke (2005)[24], which showed how a simple, pictorial extension of Dirac notation …

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 …

We compare two possible ways of defining a category of 1-combs, the first intensionally as
coend optics and the second extensionally as a quotient by the operational behaviour of 1 …

To date, there has been no experimental evidence that invalidates quantum theory. Yet it
may only be an effective description of the world, in the same way that classical physics is an …

We introduce a novel compositional description of Feynman diagrams, with well-defined
categorical semantics as morphisms in a dagger-compact category. Our chosen setting is …

An operational probabilistic theory where all systems are classical, and all pure states of
composite systems are entangled, is constructed. The theory is endowed with a rule for …