221 citations · 1.2k across the 21 of their papers we have counts for
23 papers · 1 filter
Bell nonlocality does not imply violation of nonlocal games
Ricardo Faleiro, Lucas E. A. Porto, Marco Túlio Quintino +1
Nonlocal games offer a conceptually clear way to reason about Bell nonlocality. However, we show that as originally defined, and most commonly used, i.e. with a deterministic predi…
Purification enables an unbounded query separation in sequential quantum channel discrimination
Zoe G. del Toro, Marco Túlio Quintino, Jessica Bavaresco
Purifications are often used as a convenient mathematical representation of quantum states and channels when constructing protocols for quantum information processing tasks. Althou…
Deterministic transformations between unitary operations: Exponential advantage with adaptive quantum circuits and the power of indefinite causality
Marco Túlio Quintino, Daniel Ebler
This work analyses the performance of quantum circuits and general processes to transform uses of an arbitrary unitary operation into another unitary operation . When…
Unitary channel discrimination beyond group structures: Advantages of sequential and indefinite-causal-order strategies
Jessica Bavaresco, Mio Murao, Marco Túlio Quintino
For minimum-error channel discrimination tasks that involve only unitary channels, we show that sequential strategies may outperform the parallel ones. Additionally, we show that g…
Simple and maximally robust processes with no classical common-cause or direct-cause explanation
Marcello Nery, Marco Túlio Quintino, Philippe Allard Guérin +2
Guided by the intuition of coherent superposition of causal relations, recent works presented quantum processes without classical common-cause and direct-cause explanation, that is…
Strict hierarchy between parallel, sequential, and indefinite-causal-order strategies for channel discrimination
Jessica Bavaresco, Mio Murao, Marco Túlio Quintino
We present an instance of a task of minimum-error discrimination of two qubit-qubit quantum channels for which a sequential strategy outperforms any parallel strategy. We then esta…
Bell nonlocality with a single shot
Mateus Araújo, Flavien Hirsch, Marco Túlio Quintino
In order to reject the local hidden variables hypothesis, the usefulness of a Bell inequality can be quantified by how small a p-value it will give for a physical experiment. Here…
Consequences of preserving reversibility in quantum superchannels
Wataru Yokojima, Marco Túlio Quintino, Akihito Soeda +1
Similarly to quantum states, quantum operations can also be transformed by means of quantum superchannels, also known as process matrices. Quantum superchannels with multiple slots…
Probabilistic exact universal quantum circuits for transforming unitary operations
Marco Túlio Quintino, Qingxiuxiong Dong, Atsushi Shimbo +2
This paper addresses the problem of designing universal quantum circuits to transform uses of a -dimensional unitary input-operation into a unitary output-operation in a pro…
Distributed sampling, quantum communication witnesses, and measurement incompatibility
Leonardo Guerini, Marco Túlio Quintino, Leandro Aolita
We study prepare-and-measure experiments where the sender (Alice) receives trusted quantum inputs but has an untrusted state-preparation device and the receiver (Bob) has a fully-u…
Semi-device-independent certification of indefinite causal order
Jessica Bavaresco, Mateus Araújo, Časlav Brukner +1
When transforming pairs of independent quantum operations according to the fundamental rules of quantum theory, an intriguing phenomenon emerges: some such higher-order operations…
Implementing positive maps with multiple copies of an input state
Qingxiuxiong Dong, Marco Túlio Quintino, Akihito Soeda +1
Valid transformations between quantum states are necessarily described by completely positive maps, instead of just positive maps. Positive but not completely positive maps such as…
Quantum measurement incompatibility does not imply Bell nonlocality
Flavien Hirsch, Marco Túlio Quintino, Nicolas Brunner
We discuss the connection between the incompatibility of quantum measurements, as captured by the notion of joint measurability, and the violation of Bell inequalities. Specificall…
Most incompatible measurements for robust steering tests
Jessica Bavaresco, Marco Túlio Quintino, Leonardo Guerini +3
We address the problem of characterizing the steerability of quantum states under restrictive measurement scenarios, i.e., the problem of determining whether a quantum state can de…
Super-Activation of Quantum Steering
Marco Túlio Quintino, Marcus Huber, Nicolas Brunner
We consider Einstein-Podolsky-Rosen steering in the regime where the parties can perform collective measurements on many copies of a given shared entangled state. We derive a simpl…
Better local hidden variable models for two-qubit Werner states and an upper bound on the Grothendieck constant
Flavien Hirsch, Marco Túlio Quintino, Tamás Vértesi +2
We consider the problem of reproducing the correlations obtained by arbitrary local projective measurements on the two-qubit Werner state …
On the tightness of correlation inequalities with no quantum violation
Ravishankar Ramanathan, Marco Túlio Quintino, Ana Belén Sainz +2
We study the faces of the set of quantum correlations, i.e., the Bell and noncontextuality inequalities without any quantum violation. First, we investigate the question whether ev…
Entanglement without hidden nonlocality
Flavien Hirsch, Marco Túlio Quintino, Joseph Bowles +2
We consider Bell tests in which the distant observers can perform local filtering before testing a Bell inequality. Notably, in this setup, certain entangled states admitting a loc…
Incompatible quantum measurements admitting a local hidden variable model
Marco Túlio Quintino, Joseph Bowles, Flavien Hirsch +1
The observation of quantum nonlocality, i.e. quantum correlations violating a Bell inequality, implies the use of incompatible local quantum measurements. Here we consider the conv…
Sufficient criterion for guaranteeing that a two-qubit state is unsteerable
Joseph Bowles, Flavien Hirsch, Marco Túlio Quintino +1
Quantum steering can be detected via the violation of steering inequalities, which provide sufficient conditions for the steerability of quantum states. Here we discuss the convers…
Inequivalence of entanglement, steering, and Bell nonlocality for general measurements
Marco Túlio Quintino, Tamás Vértesi, Daniel Cavalcanti +4
Einstein-Podolsky-Rosen steering is a form of inseparability in quantum theory commonly acknowledged to be intermediate between entanglement and Bell nonlocality. However, this sta…
All noncontextuality inequalities for the n-cycle scenario
Mateus Araújo, Marco Túlio Quintino, Costantino Budroni +2
The problem of separating classical from quantum correlations is in general intractable and has been solved explicitly only in few cases. In particular, known methods cannot provid…
Tests of Bell inequality with arbitrarily low photodetection efficiency and homodyne measurements
Mateus Araújo, Marco Túlio Quintino, Daniel Cavalcanti +3
We show that hybrid local measurements combining homodyne measurements and photodetection provide violations of a Bell inequality with arbitrarily low photodetection efficiency. Th…