Publications (195)
Certifying the dimension of classical and quantum systems in a prepare-and-measure scenario with independent devices
Joseph Bowles, Marco Tulio Quintino, Nicolas Brunner
We consider the problem of testing the dimension of uncharacterised classical and quantum systems in a prepare-and-measure setup. Here we assume the preparation and measurement dev…
Extractable Work from Correlations
Martà Perarnau-Llobet, Karen V. Hovhannisyan, Marcus Huber +3
Work and quantum correlations are two fundamental resources in thermodynamics and quantum information theory. In this work we study how to use correlations among quantum systems to…
Superactivation of genuine multipartite Bell nonlocality from two-party entanglement
Markus Miethlinger, Riccardo Castellano, Pavel Sekatski +1
Characterizing the relation between entanglement and Bell nonlocality is a long-standing open problem, notably challenging in the multipartite case. Here we investigate the effect…
Thermodynamic Computing via Autonomous Quantum Thermal Machines
Patryk Lipka-Bartosik, Martà Perarnau-Llobet, Nicolas Brunner
We develop a physics-based model for classical computation based on autonomous quantum thermal machines. These machines consist of few interacting quantum bits (qubits) connected t…
Towards the device-independent certification of a quantum memory
Pavel Sekatski, Jean-Daniel Bancal, Marie Ioannou +2
Quantum memories represent one of the main ingredients of future quantum communication networks. Their certification is therefore a key challenge. Here we develop efficient certifi…
Bell inequalities for three systems and arbitrarily many measurement outcomes
Basile Grandjean, Yeong-Cherng Liang, Jean-Daniel Bancal +2
We present a family of Bell inequalities for three parties and arbitrarily many outcomes, which can be seen as a natural generalization of the Mermin Bell inequality. For a small n…
Small quantum absorption refrigerator in the transient regime: time scales, enhanced cooling and entanglement
Jonatan Bohr Brask, Nicolas Brunner
A small quantum absorption refrigerator, consisting of three qubits, is discussed in the transient regime. We discuss time scales for coherent dynamics, damping, and approach to th…
Fast semidefinite programming with feedforward neural networks
Tamás Kriváchy, Yu Cai, Joseph Bowles +2
Semidefinite programming is an important optimization task, often used in time-sensitive applications. Though they are solvable in polynomial time, in practice they can be too slow…
The power of quantum catalytic local operations
Patryk Lipka-Bartosik, Jessica Bavaresco, Nicolas Brunner +1
A key result in entanglement theory is that the addition of a catalyst dramatically enlarges the set of possible state transformations via local operations and classical communicat…
Quantifying measurement incompatibility of mutually unbiased bases
Sébastien Designolle, Paul Skrzypczyk, Florian Fröwis +1
Quantum measurements based on mutually unbiased bases are commonly used in quantum information processing, as they are generally viewed as being maximally incompatible and compleme…
Towards a minimal example of quantum nonlocality without inputs
Sadra Boreiri, Antoine Girardin, Bora Ulu +3
The network scenario offers interesting new perspectives on the phenomenon of quantum nonlocality. Notably, when considering networks with independent sources, it is possible to de…
Postquantum steering
Ana Belen Sainz, Nicolas Brunner, Daniel Cavalcanti +2
The discovery of postquantum nonlocality, i.e., the existence of nonlocal correlations that are stronger than any quantum correlations but nevertheless consistent with the no-signa…
Persistency of entanglement and nonlocality in multipartite quantum systems
Nicolas Brunner, Tamas Vertesi
The behaviour under particle loss of entanglement and nonlocality is investigated in multipartite quantum systems. In particular, we define a notion of persistency of nonlocality,…
Trading symmetry for Hilbert-space dimension in Bell-inequality violation
Hsin-Yu Hsu, Gelo Noel M. Tabia, Kai-Siang Chen +4
In quantum information, asymmetry, i.e., the lack of symmetry, is a resource allowing one to accomplish certain tasks that are otherwise impossible. Similarly, in a Bell test using…
Thermodynamic cost of creating correlations
Marcus Huber, Martà Perarnau-Llobet, Karen V. Hovhannisyan +4
We investigate the fundamental limitations imposed by thermodynamics for creating correlations. Considering a collection of initially uncorrelated thermal quantum systems, we ask h…
Noise-Robust and Loss-Tolerant Quantum Steering with Qudits
Vatshal Srivastav, Natalia Herrera Valencia, Will McCutcheon +5
A primary requirement for a robust and unconditionally secure quantum network is the establishment of quantum nonlocal correlations over a realistic channel. While loophole-free te…
Self-testing quantum states and measurements in the prepare-and-measure scenario
Armin Tavakoli, JÄdrzej Kaniewski, Tamás Vértesi +2
The goal of self-testing is to characterize an a priori unknown quantum system based solely on measurement statistics, i.e. using an uncharacterized measurement device. Here we dev…
Bell nonlocality and Bayesian game theory
Nicolas Brunner, Noah Linden
We discuss a connection between Bell nonlocality and Bayesian games. This link offers interesting perspectives for Bayesian games, namely to allow the players to receive advice in…
Device-independent quantum key distribution secure against collective attacks
Stefano Pironio, Antonio Acin, Nicolas Brunner +3
Device-independent quantum key distribution (DIQKD) represents a relaxation of the security assumptions made in usual quantum key distribution (QKD). As in usual QKD, the security…
Simulation of partial entanglement with nonsignaling resources
Nicolas Brunner, Nicolas Gisin, Sandu Popescu +1
With the goal of gaining a deeper understanding of quantum non-locality, we decompose quantum correlations into more elementary non-local correlations. We show that the correlation…
Genuine quantum nonlocality in the triangle network
Marc-Olivier Renou, Elisa Bäumer, Sadra Boreiri +3
Quantum networks allow in principle for completely novel forms of quantum correlations. In particular, quantum nonlocality can be demonstrated here without the need of having vario…
Classical simulation of entanglement swapping with bounded communication
Cyril Branciard, Nicolas Brunner, Harry Buhrman +5
Entanglement appears under two different forms in quantum theory, namely as a property of states of joint systems and as a property of measurement eigenstates in joint measurements…
Loophole-free Einstein-Podolsky-Rosen experiment via quantum steering
Bernhard Wittmann, Sven Ramelow, Fabian Steinlechner +5
Tests of the predictions of quantum mechanics for entangled systems have provided increasing evidence against local realistic theories. However, there still remains the crucial cha…
A neural network oracle for quantum nonlocality problems in networks
Tamás Kriváchy, Yu Cai, Daniel Cavalcanti +3
Characterizing quantum nonlocality in networks is a challenging, but important problem. Using quantum sources one can achieve distributions which are unattainable classically. A ke…
Nonlocality of and Dicke states subject to losses
Tomer Jack Barnea, Gilles Pütz, Jonatan Bohr Brask +3
We discuss the nonlocality of the and the Dicke states subject to losses. We consider two noise models, namely loss of excitations and loss of particles, and investigate how mu…
Quantum catalysis in cavity quantum electrodynamics
A. de Oliveira Junior, Martà Perarnau-Llobet, Nicolas Brunner +1
Catalysis plays a key role in many scientific areas, most notably in chemistry and biology. Here we present a catalytic process in a paradigmatic quantum optics setup, namely the J…
Single-electron entanglement and nonlocality
David Dasenbrook, Joseph Bowles, Jonatan Bohr Brask +3
Motivated by recent progress in electron quantum optics, we revisit the question of single-electron entanglement, specifically whether the state of a single electron in a superposi…
A Quantum Mechanical Pendulum Clock
Matteo Brunelli, Mohammad Mehboudi, Nicolas Brunner +1
We investigate an optomechanical system as a model of an autonomous mechanical pendulum clock in the quantum regime, whose operation relies only on incoherent (thermal) resources.…
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…
Genuine hidden quantum nonlocality
Flavien Hirsch, Marco Túlio Quintino, Joseph Bowles +1
The nonlocality of certain quantum states can be revealed by using local filters before performing a standard Bell test. This phenomenon, known as hidden nonlocality, has been so f…
Noise-robust proofs of quantum network nonlocality
Sadra Boreiri, Bora Ulu, Nicolas Brunner +1
Quantum networks allow for novel forms of quantum nonlocality. By exploiting the combination of entangled states and entangled measurements, strong nonlocal correlations can be gen…
Quantifying photonic high-dimensional entanglement
Anthony Martin, Thiago Guerreiro, Alexey Tiranov +5
High-dimensional entanglement offers promising perspectives in quantum information science. In practice, however, the main challenge is to devise efficient methods to characterize…
Unlimited One-Way Steering
Pavel Sekatski, Florian Giraud, Roope Uola +1
This work explores the asymmetry of quantum steering in a setup using high-dimensional entanglement. We construct entangled states with the following properties: one party (A…
All quantum resources provide an advantage in exclusion tasks
Roope Uola, Tom Bullock, Tristan Kraft +2
A key ingredient in quantum resource theories is a notion of measure. Such as a measure should have a number of fundamental properties, and desirably also a clear operational meani…
Bound non-locality and activation
Nicolas Brunner, Daniel Cavalcanti, Alejo Salles +1
We investigate non-locality distillation using measures of non-locality based on the Elitzur-Popescu-Rohrlich decomposition. For a certain number of copies of a given non-local cor…
Practical self-testing quantum random number generator based on an energy bound
Davide Rusca, Thomas van Himbeeck, Anthony Martin +5
We present a scheme for a self-testing quantum random number generator. Compared to the fully device-independent model, our scheme requires an extra natural assumption, namely that…
Genuinely multipartite entangled quantum states with fully local hidden variable models and hidden multipartite nonlocality
Joseph Bowles, Jérémie Francfort, Mathieu Fillettaz +2
The relation between entanglement and nonlocality is discussed in the case of multipartite quantum systems. We show that, for any number of parties, there exist genuinely multipart…
Symmetric observations without symmetric causal explanations
Christian William, Patrick Remy, Jean-Daniel Bancal +3
Inferring causal models from observed correlations is a challenging task, crucial to many areas of science. In order to alleviate the computational effort when sifting through poss…
Constraints on nonlocality in networks from no-signaling and independence
Nicolas Gisin, Jean-Daniel Bancal, Yu Cai +5
Generalising the concept of Bell nonlocality to networks leads to novel forms of correlations, the characterization of which is however challenging. Here we investigate constraints…
Catalytic Activation of Bell Nonlocality
Jessica Bavaresco, Nicolas Brunner, Antoine Girardin +2
The correlations of certain entangled states can be perfectly simulated classically via a local model. Hence such states are termed Bell local, as they cannot lead to Bell inequali…
Device-dependent and device-independent quantum key distribution without a shared reference frame
Joshua A. Slater, Cyril Branciard, Nicolas Brunner +1
Standard quantum key distribution (QKD) protocols typically assume that the distant parties share a common reference frame. In practice, however, establishing and maintaining a goo…
Testing the Hilbert space dimension
Nicolas Brunner, Stefano Pironio, Antonio Acin +3
Given a set of correlations originating from measurements on a quantum state of unknown Hilbert space dimension, what is the minimal dimension d necessary to describes such correla…
Towards practical and fast Quantum Cryptography
Nicolas Gisin, Gregoire Ribordy, Hugo Zbinden +3
We present a new protocol for practical quantum cryptography, tailored for an implementation with weak coherent pulses. The key is obtained by a very simple time-of-arrival measure…
Set coherence: basis-independent quantification of quantum coherence
Sébastien Designolle, Roope Uola, Kimmo Luoma +1
The coherence of an individual quantum state can be meaningfully discussed only when referring to a preferred basis. This arbitrariness can however be lifted when considering sets…
Couplers for Non-Locality Swapping
Paul Skrzypczyk, Nicolas Brunner
Studying generalized non-local theories brings insight to the foundations of quantum mechanics. Here we focus on non-locality swapping, the analogue of quantum entanglement swappin…
Semi-device-independent security of one-way quantum key distribution
Marcin Pawlowski, Nicolas Brunner
By testing nonlocality, the security of entanglement-based quantum key distribution (QKD) can be enhanced to being 'device-independent'. Here we ask whether such a strong form of s…
Network Quantum Steering
Benjamin D. M. Jones, Ivan Å upiÄ, Roope Uola +2
The development of large-scale quantum networks promises to bring a multitude of technological applications as well as shed light on foundational topics, such as quantum nonlocalit…
Correlations in star networks: from Bell inequalities to network inequalities
Armin Tavakoli, Marc-Olivier Renou, Nicolas Gisin +1
The problem of characterizing classical and quantum correlations in networks is considered. Contrary to the usual Bell scenario, where distant observers share a physical system emi…
Device-independent certification of entangled measurements
Rafael Rabelo, Melvyn Ho, Daniel Cavalcanti +2
We present a device-independent protocol to test if a given black-box measurement device is entangled, that is, has entangled eigenstates. Our scheme involves three parties and is…
Operational definition of the temperature of a quantum state
Patryk Lipka-Bartosik, Martà Perarnau-Llobet, Nicolas Brunner
Temperature is usually defined for physical systems at thermal equilibrium. Nevertheless one may wonder if it would be possible to attribute a meaningful notion of temperature to a…
Limits on correlations in networks for quantum and no-signaling resources
Marc-Olivier Renou, Yuyi Wang, Sadra Boreiri +3
A quantum network consists of independent sources distributing entangled states to distant nodes which can then perform entangled measurements, thus establishing correlations acros…
Building separable approximations for quantum states via neural networks
Antoine Girardin, Nicolas Brunner, Tamás Kriváchy
Finding the closest separable state to a given target state is a notoriously difficult task, even more difficult than deciding whether a state is entangled or separable. To tackle…
Entanglement enhances cooling in microscopic quantum fridges
Nicolas Brunner, Marcus Huber, Noah Linden +3
Small self-contained quantum thermal machines function without external source of work or control, but using only incoherent interactions with thermal baths. Here we investigate th…
Unbounded sequence of observers exhibiting Einstein-Podolsky-Rosen steering
Akshata Shenoy H, Sébastien Designolle, Flavien Hirsch +3
A sequential steering scenario is investigated, where multiple Bobs aim at demonstrating steering using successively the same half of an entangled quantum state. With isotropic ent…
Bell nonlocality in quantum networks with unreliable sources: Loophole-free postelection via self-testing
Sadra Boreiri, Nicolas Brunner, Pavel Sekatski
We discuss Bell nonlocality in quantum networks with unreliable sources. Our main result is a condition on the observed data which ensures that inconclusive events can be safely di…
Absolutely entangled sets of pure states for bipartitions and multipartitions
Baichu Yu, Pooja Jayachandran, Adam Burchardt +3
A set of quantum states is said to be absolutely entangled, when at least one state in the set remains entangled for any definition of subsystems, i.e. for any choice of the global…
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…
Semi-device-independent bounds on entanglement
Yeong-Cherng Liang, Tamas Vertesi, Nicolas Brunner
Detection and quantification of entanglement in quantum resources are two key steps in the implementation of various quantum-information processing tasks. Here, we show that Bell-t…
Quantum entanglement in the triangle network
Tristan Kraft, Sébastien Designolle, Christina Ritz +3
Beyond future applications, quantum networks open interesting fundamental perspectives, notably novel forms of quantum correlations. In this work we discuss quantum correlations in…
Anomalous Weak Values Without Post-Selection
Alastair A. Abbott, Ralph Silva, Julian Wechs +2
A weak measurement performed on a pre- and post-selected quantum system can result in an average value that lies outside of the observable's spectrum. This effect, usually referred…
Hybrid Thermal Machines: Generalized Thermodynamic Resources for Multitasking
Gonzalo Manzano, Rafael Sánchez, Ralph Silva +4
Thermal machines perform useful tasks--such as producing work, cooling, or heating--by exchanging energy, and possibly additional conserved quantities such as particles, with reser…
Algorithmic construction of local models for entangled quantum states: optimization for two-qubit states
Mathieu Fillettaz, Flavien Hirsch, Sébastien Designolle +1
The correlations of certain entangled quantum states can be fully reproduced via a local model. We discuss in detail the practical implementation of an algorithm for constructing l…
Quantum measurement incompatibility in subspaces
Roope Uola, Tristan Kraft, Sébastien Designolle +5
We consider the question of characterising the incompatibility of sets of high-dimensional quantum measurements. We introduce the concept of measurement incompatibility in subspace…
A small quantum absorption refrigerator with reversed couplings
Ralph Silva, Paul Skrzypczyk, Nicolas Brunner
Small quantum absorption refrigerators have recently attracted renewed attention. Here we present a missing design of a two-qubit fridge, the main feature of which is that one of t…
Partial list of bipartite Bell inequalities with four binary settings
Nicolas Brunner, Nicolas Gisin
We give a partial list of 26 tight Bell inequalities for the case where Alice and Bob choose among four two-outcome measurements. All tight Bell inequalities with less settings are…
Quantum nonlocality in networks can be demonstrated with an arbitrarily small level of independence between the sources
Ivan Å upiÄ, Jean-Daniel Bancal, Nicolas Brunner
Quantum nonlocality can be observed in networks even in the case where every party can only perform a single measurement, i.e. does not receive any input. So far, this effect has b…
Closing the detection loophole in Bell experiments using qudits
Tamas Vertesi, Stefano Pironio, Nicolas Brunner
We show that the detection efficiencies required for closing the detection loophole in Bell tests can be significantly lowered using quantum systems of dimension larger than two. W…
Entanglement and non-locality are different resources
Nicolas Brunner, Nicolas Gisin, Valerio Scarani
Bell's theorem states that, to simulate the correlations created by measurement on pure entangled quantum states, shared randomness is not enough: some "non-local" resources are re…
Testing a Bell inequality in multi-pair scenarios
Jean-Daniel Bancal, Cyril Branciard, Nicolas Brunner +3
To date, most efforts to demonstrate quantum nonlocality have concentrated on systems of two (or very few) particles. It is however difficult in many experiments to address individ…
Guess your neighbour's input: no quantum advantage but an advantage for quantum theory
Antonio AcÃn, Mafalda L. Almeida, Remigiusz Augusiak +1
Quantum mechanics dramatically differs from classical physics, allowing for a wide range of genuinely quantum phenomena. The goal of quantum information is to understand informatio…
Stronger Welch Bounds and Optimal Approximate -Designs
Riccardo Castellano, Dmitry Grinko, Sadra Boreiri +2
A fundamental question asks how uniformly finite sets of pure quantum states can be distributed in a Hilbert space. The Welch bounds address this question, and are saturated by …
Self-testing non-projective quantum measurements in prepare-and-measure experiments
Armin Tavakoli, Massimiliano Smania, Tamás Vértesi +2
Self-testing represents the strongest form of certification of a quantum system. Here we investigate theoretically and experimentally the question of self-testing non-projective qu…
Quantum cryptography with and without entanglement
Nicolas Gisin, Nicolas Brunner
Quantum cryptography is reviewed, first using entanglement both for the intuition and for the experimental realizations. Next, the implementation is simplified in several steps unt…
Tight steering inequalities from generalized entropic uncertainty relations
Tamás Kriváchy, Florian Fröwis, Nicolas Brunner
We establish a general connection between entropic uncertainty relations, Einstein-Podolsky-Rosen steering, and joint measurability. Specifically, we construct steering inequalitie…
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…
Device-independent security of quantum cryptography against collective attacks
Antonio Acin, Nicolas Brunner, Nicolas Gisin +3
We present the optimal collective attack on a Quantum Key Distribution (QKD) protocol in the "device-independent" security scenario, where no assumptions are made about the way the…
Device Independent Quantum Key Activation
Bora Ulu, Nicolas Brunner, Mirjam Weilenmann
Device-independent quantum key distribution (DIQKD) allows two distant parties to establish a secret key, based only on the observed Bell nonlocal distribution. It remains however,…
Simulability of high-dimensional quantum measurements
Marie Ioannou, Pavel Sekatski, Sébastien Designolle +3
We investigate the compression of quantum information with respect to a given set of high-dimensional measurements. This leads to a notion of simulability, where we d…
Limits on non-local correlations from the structure of the local state space
Peter Janotta, Christian Gogolin, Jonathan Barrett +1
The outcomes of measurements on entangled quantum systems can be nonlocally correlated. However, while it is easy to write down toy theories allowing arbitrary nonlocal correlation…
Communication cost of simulating entanglement swapping
Nicolas Brunner, Cyril Branciard, Nicolas Gisin +1
Entanglement appears in two different ways in quantum mechanics, namely as a property of states and as a property of measurement outcomes in joint measurements. By combining these…
Temporal multimode storage of entangled photon pairs
Alexey Tiranov, Peter C. Strassmann, Jonathan Lavoie +10
Multiplexed quantum memories capable of storing and processing entangled photons are essential for the development of quantum networks. In this context, we demonstrate the simultan…
Closing the detection loophole in multipartite Bell tests using GHZ states
Karoly F. Pal, Tamas Vertesi, Nicolas Brunner
We investigate the problem of closing the detection loophole in multipartite Bell tests, and show that the required detection efficiencies can be significantly lowered compared to…
The minimal example of quantum network Bell nonlocality
Erwan Don, Jessica Bavaresco, Patryk Lipka-Bartosik +3
In recent years, the study of Bell nonlocality has been generalized to quantum networks, where multiple independent sources distribute physical systems to distant parties who perfo…
Classical communication cost of quantum steering
Ana Belén Sainz, Leandro Aolita, Nicolas Brunner +2
Quantum steering is observed when performing appropriate local measurements on an entangled state. Here we discuss the possibility of simulating classically this effect, using clas…
A self-testing quantum random number generator
Tommaso Lunghi, Jonatan Bohr Brask, Charles Ci Wen Lim +5
The generation of random numbers is a task of paramount importance in modern science. A central problem for both classical and quantum randomness generation is to estimate the entr…
Quantification of multidimensional entanglement stored in a crystal
Alexey Tiranov, Sébastien Designolle, Emmanuel Zambrini Cruzeiro +5
The use of multidimensional entanglement opens new perspectives for quantum information processing. However, an important challenge in practice is to certify and characterize multi…
Bell tests for continuous variable systems using hybrid measurements and heralded amplifiers
Jonatan Bohr Brask, Nicolas Brunner, Daniel Cavalcanti +1
We present Bell tests for optical continuous variable systems, combining both hybrid measurements (i.e. measuring both particle and wave aspects of light) and heralded amplifiers.…
Possibilistic approach to network nonlocality
Antoine Restivo, Nicolas Brunner, Denis Rosset
The investigation of Bell nonlocality traditionally relies on joint probabilities of observing certain measurement outcomes. In this work we explore a possibilistic approach, where…
Quantum teleportation of single-electron states
Edvin Olofsson, Peter Samuelsson, Nicolas Brunner +1
We consider a scheme for on-demand teleportation of a dual-rail electron qubit state, based on single-electron sources and detectors. The scheme has a maximal efficiency of 25%, wh…
Quantum Thermal Machine as a Thermometer
Patrick P. Hofer, Jonatan Bohr Brask, Martà Perarnau-Llobet +1
We propose the use of a quantum thermal machine for low-temperature thermometry. A hot thermal reservoir coupled to the machine allows for simultaneously cooling the sample while d…
A framework for the study of symmetric full-correlation Bell-like inequalities
Jean-Daniel Bancal, Cyril Branciard, Nicolas Brunner +2
Full-correlation Bell-like inequalities represent an important subclass of Bell-like inequalities that have found applications in both a better understanding of fundamental physics…
Receiver-Device-Independent Quantum Key Distribution
Marie Ioannou, Maria Ana Pereira, Davide Rusca +9
We present protocols for quantum key distribution in a prepare-and-measure setup with an asymmetric level of trust. While the device of the sender (Alice) is partially characterize…
Sequential random access codes and self-testing of quantum measurement instruments
Karthik Mohan, Armin Tavakoli, Nicolas Brunner
Quantum Random Access Codes (QRACs) are key tools for a variety of protocols in quantum information theory. These are commonly studied in prepare-and-measure scenarios in which a s…
Local hidden variable models for entangled quantum states using finite shared randomness
Joseph Bowles, Flavien Hirsch, Marco Túlio Quintino +1
The statistics of local measurements performed on certain entangled states can be reproduced using a local hidden variable (LHV) model. While all known models make use of an infini…
Genuine network quantum nonlocality and self-testing
Ivan Å upiÄ, Jean-Daniel Bancal, Yu Cai +1
The network structure offers in principle the possibility for novel forms of quantum nonlocal correlations, that are proper to networks and cannot be traced back to standard quantu…
Self-testing nonlocality without entanglement
Ivan Å upiÄ, Nicolas Brunner
Quantum theory allows for nonlocality without entanglement. Notably, there exist bipartite quantum measurements consisting of only product eigenstates, yet they cannot be implement…
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 $Ï= v |Ï_- > <Ï_- | + (1- v ) \frac{1}{…
Bell nonlocality
Nicolas Brunner, Daniel Cavalcanti, Stefano Pironio +2
Bell's 1964 theorem, which states that the predictions of quantum theory cannot be accounted for by any local theory, represents one of the most profound developments in the founda…
Unifying paradigms of quantum refrigeration: fundamental limits of cooling and associated work costs
Fabien Clivaz, Ralph Silva, Géraldine Haack +3
In classical thermodynamics the work cost of control can typically be neglected. On the contrary, in quantum thermodynamics the cost of control constitutes a fundamental contributi…
Testing nonlocality of a single photon without a shared reference frame
Jonatan Bohr Brask, Rafael Chaves, Nicolas Brunner
The question of testing the nonlocality of a single photon has raised much debate over the last years. The controversy is intimately related to the issue of providing a common refe…