152 citations · 469 across the 20 of their papers we have counts for
23 papers
Bell's go theorem: regaining local causality with a new notion of realism
Lorenzo Catani, Nesta van der Schaaf, Rui Soares Barbosa
Bell's theorem is popularly stated as the inconsistency of quantum theory with local realism. Realism is here formalized by the ontological models framework, where elements of real…
Algebraic paradoxes in adaptive quantum computation
Samson Abramsky, Rui Soares Barbosa, Carmen Constantin +1
Measurement-based quantum computation (MBQC) is a universal model of quantum computation whose full power requires adaptivity. Contextuality is known to power quantum advantage in…
A bundle perspective on contextuality: Empirical models and simplicial distributions on bundle scenarios
Rui Soares Barbosa, Aziz Kharoof, Cihan Okay
This paper provides a bundle perspective to contextuality by introducing new categories of contextuality scenarios based on bundles of simplicial complexes and simplicial sets. The…
Combining contextuality and causality: a game semantics approach
Samson Abramsky, Rui Soares Barbosa, Amy Searle
We develop an approach to combining contextuality with causality, which is general enough to cover causal background structure, adaptive measurement-based quantum computation, and…
Quantum circuits for measuring weak values, Kirkwood--Dirac quasiprobability distributions, and state spectra
Rafael Wagner, Zohar Schwartzman-Nowik, Ismael L. Paiva +5
Weak values and Kirkwood--Dirac (KD) quasiprobability distributions have been independently associated with both foundational issues in quantum theory and advantages in quantum met…
Inequalities witnessing coherence, nonlocality, and contextuality
Rafael Wagner, Rui Soares Barbosa, Ernesto F. Galvão
Quantum coherence, nonlocality, and contextuality are key resources for quantum advantage in metrology, communication, and computation. We introduce a graph-based approach to deriv…
Sheaf representation of monoidal categories
Rui Soares Barbosa, Chris Heunen
Every small monoidal category with universal finite joins of central idempotents is monoidally equivalent to the category of global sections of a sheaf of local monoidal categories…
Closing Bell: Boxing black box simulations in the resource theory of contextuality
Rui Soares Barbosa, Martti Karvonen, Shane Mansfield
This chapter contains an exposition of the sheaf-theoretic framework for contextuality emphasising resource-theoretic aspects, as well as some original results on this topic. In pa…
The logic of contextuality
Samson Abramsky, Rui Soares Barbosa
Contextuality is a key signature of quantum non-classicality, which has been shown to play a central role in enabling quantum advantage for a wide range of information-processing a…
Compiling quantamorphisms for the IBM Q Experience
Ana Neri, Rui Soares Barbosa, José N. Oliveira
Based on the connection between the categorical derivation of classical programs from specifications and the category-theoretic approach to quantum physics, this paper contributes…
Continuous-variable nonlocality and contextuality
Rui Soares Barbosa, Tom Douce, Pierre-Emmanuel Emeriau +2
Contextuality is a non-classical behaviour that can be exhibited by quantum systems. It is increasingly studied for its relationship to quantum-over-classical advantages in informa…
A comonadic view of simulation and quantum resources
Samson Abramsky, Rui Soares Barbosa, Martti Karvonen +1
We study simulation and quantum resources in the setting of the sheaf-theoretic approach to contextuality and non-locality. Resources are viewed behaviourally, as empirical models.…
Minimum quantum resources for strong non-locality
Samson Abramsky, Rui Soares Barbosa, Giovanni Carù +3
We analyse the minimum quantum resources needed to realise strong non-locality, as exemplified e.g. by the classical GHZ construction. It was already known that no two-qubit system…
A complete characterisation of All-versus-Nothing arguments for stabiliser states
Samson Abramsky, Rui Soares Barbosa, Giovanni Carù +1
An important class of contextuality arguments in quantum foundations are the All-versus-Nothing (AvN) proofs, generalising a construction originally due to Mermin. We present a gen…
The contextual fraction as a measure of contextuality
Samson Abramsky, Rui Soares Barbosa, Shane Mansfield
We consider the contextual fraction as a quantitative measure of contextuality of empirical models, i.e. tables of probabilities of measurement outcomes in an experimental scenario…
The Quantum Monad on Relational Structures
Samson Abramsky, Rui Soares Barbosa, Nadish de Silva +1
Homomorphisms between relational structures play a central role in finite model theory, constraint satisfaction and database theory. A central theme in quantum computation is to sh…
Possibilities Determine the Combinatorial Structure of Probability Polytopes
Samson Abramsky, Rui Soares Barbosa, Kohei Kishida +2
We study the set of no-signalling empirical models on a measurement scenario, and show that the combinatorial structure of the no-signalling polytope is completely determined by th…
Contextuality, Cohomology and Paradox
Samson Abramsky, Rui Soares Barbosa, Kohei Kishida +2
Contextuality is a key feature of quantum mechanics that provides an important non-classical resource for quantum information and computation. Abramsky and Brandenburger used sheaf…
On monogamy of non-locality and macroscopic averages: examples and preliminary results
Rui Soares Barbosa
We explore a connection between monogamy of non-locality and a weak macroscopic locality condition: the locality of the average behaviour. These are revealed by our analysis as bei…
Partial and Total Ideals of Von Neumann Algebras
Nadish de Silva, Rui Soares Barbosa
A notion of partial ideal for an operator algebra is a weakening the notion of ideal where the defining algebraic conditions are enforced only in the commutative subalgebras. We sh…
Extendability in the Sheaf-theoretic Approach: Construction of Bell Models from Kochen-Specker Models
Shane Mansfield, Rui Soares Barbosa
Extendability of an empirical model was shown by Abramsky & Brandenburger to correspond in a unified manner to both locality and non-contextuality. We develop their approach by pre…
The Cohomology of Non-Locality and Contextuality
Samson Abramsky, Shane Mansfield, Rui Soares Barbosa
In a previous paper with Adam Brandenburger, we used sheaf theory to analyze the structure of non-locality and contextuality. Moreover, on the basis of this formulation, we showed…
Unsharp Values, Domains and Topoi
Andreas Doering, Rui Soares Barbosa
The so-called topos approach provides a radical reformulation of quantum theory. Structurally, quantum theory in the topos formulation is very similar to classical physics. There i…