Article
Optics
Sarah Croke
Summary: The notion of nonlocality in quantum theory suggests that information can be encoded in a composite system in a way that cannot be accessed through local measurements. However, we find that in two-dimensional subspaces, information encoded within can be accessed through local measurement and classical feedback.
Article
Optics
Debasis Mondal, Jaskaran Singh, Dagomir Kaszlikowski
Summary: Recent research shows that quantum steerability surpasses the bound set by the instrumental causal network, suggesting that quantum instrumentality cannot completely replicate the nonlocal correlations of Einstein-Podolsky-Rosen (EPR).
Article
Physics, Multidisciplinary
Ming-Liang Hu, Jia-Ru Wang, Heng Fan
Summary: This study investigates how many observers can share the nonlocal advantage of quantum coherence in a (d x d)-dimensional state. The results show that, in a given scenario, at most one observer can demonstrate this nonlocal advantage with Bob.
SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY
(2022)
Article
Quantum Science & Technology
Yu-Xia Xie, Xiao-Xiao Xu
Summary: The study investigates the nonlocal advantage of quantum coherence and quantum discord in different states, and finds their relationship with thermodynamic potential, approaching thermodynamic limits quickly with an increase in the number of spins. It also explores the relationship between quantum coherence and quantum discord versus energy in the anisotropic Heisenberg XXZ model.
QUANTUM INFORMATION PROCESSING
(2021)
Article
Physics, Multidisciplinary
Huan Cao, Marc-Olivier Renou, Chao Zhang, Gaël Masse, Xavier Coiteux-Roy, Bi-Heng Liu, Yun-Feng Huang, Chuan-Feng Li, Guang-Can Guo, Elie Wolfe
Summary: Quantum theory predicts the existence of genuinely tripartite-entangled states that cannot be obtained from local operations and unlimited shared randomness. Researchers have experimentally verified these tripartite correlations and proposed a new method for falsifying causal theories limited to bipartite nonclassical resources. The validity of this method has been demonstrated through experiments.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Ming-Liang Hu, Yu-Han Zhang, Heng Fan
Summary: The study reveals that the memory effects of the correlated dephasing channel significantly suppress the nonlocal advantage of quantum coherence, especially for input Bell-like states with one excitation. The impact of memory factors slows down the decay rate of NAQC.
Article
Physics, Multidisciplinary
Bao-Min Li, Ming-Liang Hu, Heng Fan
Summary: In this study, we investigate the nonlocal advantage of quantum coherence and entanglement for two spins coupled via the Heisenberg interaction and under intrinsic decoherence. We found that in the weak magnetic field region, nonlocal advantage of quantum coherence behaves as damped oscillation, while entanglement decays exponentially. The decay of both can be significantly suppressed by tuning the magnetic field and anisotropy of the spin interaction to optimal values determined by the decoherence rate.
Article
Quantum Science & Technology
Haesol Han, Jeonghyeon Shin, Minjin Choi, Byung Chan Kim, Soojoon Lee
Summary: Through the study of the magic pentagram problem and its connection to the magic pentagram game, this paper demonstrates the distinction between quantum and classical circuits. The findings highlight the differences between quantum and classical computation.
QUANTUM INFORMATION PROCESSING
(2022)
Article
Optics
Yu-Xia Xie
Summary: This study investigates the nonlocal advantage of quantum coherence (NAQC) for two qubits coupled via the Heisenberg interaction and embedded in their respective thermal and dephasing reservoirs. It is shown that in the presence of the Heisenberg interaction, the decay rate of NAQC can be reduced and its strength can be enhanced for certain initial states. Additionally, the Heisenberg interaction between two spins can induce the generation of NAQC from initial product states, and the generated NAQC approaches its maximum as the anisotropy of the Heisenberg interaction increases.
LASER PHYSICS LETTERS
(2021)
Article
Physics, Multidisciplinary
Yu-Xia Xie, Yu-Han Zhang
Summary: The study introduces methods to enhance thermal nonlocal advantage of quantum coherence (NAQC) in different lattice structures by introducing Dzyaloshinsky-Moriya (DM) interaction and tuning the anisotropy of spin-spin coupling. The results show a significant enhancement in NAQC and critical temperature with the introduction of DM interaction, providing a new way to achieve NAQC for quantum tasks based on spin lattices.
INTERNATIONAL JOURNAL OF THEORETICAL PHYSICS
(2021)
Article
Computer Science, Theory & Methods
Jyotirmoy Basak, Subhamoy Maitra, Prabal Paul, Animesh Roy
Summary: In this paper, the authors thoroughly investigate the performance of binary nonlocal games in terms of success probability in both classical and quantum scenarios. They find that apart from the famous CHSH game, there are other games that exhibit a higher success probability in the quantum scenario. The study emphasizes that the CHSH game is the most efficient in distinguishing between quantum and classical techniques.
CRYPTOGRAPHY AND COMMUNICATIONS-DISCRETE-STRUCTURES BOOLEAN FUNCTIONS AND SEQUENCES
(2023)
Article
Geochemistry & Geophysics
Elvira A. Dovletyarova, Olga S. Fareeva, Alexander P. Zhikharev, Ramilla A. Brykova, Evgenii L. Vorobeichik, Marina V. Slukovskaya, Martina Vitkova, Vojtech Ettler, Carolina Yanez, Alexander Neaman
Summary: The potential use of zero-valent iron (ZVI) nanoparticles for the remediation of metal contaminated soils has been widely studied, but doubts remain about their superiority compared to ZVI microparticles or natural iron oxides. This study found that under the experimental setup, ZVI nanoparticles did not prove to be superior in immobilizing metals in contaminated soil.
APPLIED GEOCHEMISTRY
(2022)
Proceedings Paper
Computer Science, Theory & Methods
Andras Gilyen, Matthew B. Hastings, Umesh Vazirani
Summary: The research demonstrates the potential of (sub)exponential quantum speed-up through a quantum algorithm following an adiabatic path of a gapped Hamiltonian with no sign problem. The algorithm efficiently finds a specific EXIT vertex in an undirected graph, but the classical algorithms face limitations in finding the EXIT vertex when given the graph via an adjacency-list oracle.
STOC '21: PROCEEDINGS OF THE 53RD ANNUAL ACM SIGACT SYMPOSIUM ON THEORY OF COMPUTING
(2021)
Article
Multidisciplinary Sciences
Nicolas Gisin, Jean-Daniel Bancal, Yu Cai, Patrick Remy, Armin Tavakoli, Emmanuel Zambrini Cruzeiro, Sandu Popescu, Nicolas Brunner
NATURE COMMUNICATIONS
(2020)
Article
Quantum Science & Technology
Jean-Daniel Bancal, Kai Redeker, Pavel Sekatski, Wenjamin Rosenfeld, Nicolas Sangouard
Summary: The article introduces a method to certify through self-testing that a device produces states on average close to a Bell state without assuming identical behavior at each run. The method is based on a Bell test free of detection and locality loopholes, enabling the successful distribution of Bell states and long-distance quantum communication.
Article
Quantum Science & Technology
Pavel Sekatski, Jean-Daniel Bancal, Xavier Valcarce, Ernest Y-Z Tan, Renato Renner, Nicolas Sangouard
Summary: Device-independent quantum key distribution aims to provide security assurances even with largely uncharacterised devices. By deriving a security proof from a generalisation of the CHSH score that takes into account the individual values of two correlation functions, higher key rates can be achieved. The additional information considered in this technique, which is available in practice, offers potential advantages for realistic photonic implementations of device-independent quantum key distribution.
Article
Physics, Multidisciplinary
Sebastien Designolle, Roope Uola, Kimmo Luoma, Nicolas Brunner
Summary: The coherence of a set of quantum systems can be characterized in a basis-independent way using the concept of set coherence, with measures that have operational meaning in discrimination games and capture the advantage offered by a given set over incoherent ones. This notion of set coherence is also connected to resource-theoretic approaches developed for quantum systems.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Benjamin D. M. Jones, Ivan SupiC, Roope Uola, Nicolas Brunner, Paul Skrzypczyk
Summary: The development of large-scale quantum networks can bring various technological applications and shed light on foundational topics such as quantum nonlocality. This study focuses on scenarios where sources within the network are statistically independent, leading to network nonlocality. By introducing network steering and NLHS models, relationships between certain results are highlighted, demonstrating the existence of network nonlocality.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Marie Ioannou, Pavel Sekatski, Alastair A. Abbott, Denis Rosset, Jean-Daniel Bancal, Nicolas Brunner
Summary: In this paper, we discuss quantum key distribution protocols and their security analysis, considering a receiver-device-independent (RDI) model. We assume that the sender's device is partially characterized, while the receiver's device can be represented as a black-box. By utilizing protocols with sufficiently many states, we show that a secret key can be established even with arbitrarily low transmission rates of the quantum channel. We also discuss the practical application of the hypothesis of bounded overlaps in devices.
NEW JOURNAL OF PHYSICS
(2022)
Article
Physics, Multidisciplinary
Pavel Sekatski, Sadra Boreiri, Nicolas Brunner
Summary: This study investigates the demonstration of quantum nonlocality in networks with independent sources and proposes a method for self-testing the underlying quantum strategy. By applying these findings to the triangle network, the researchers show that the network exhibits genuine network quantum nonlocality and certifiable randomness.
PHYSICAL REVIEW LETTERS
(2023)
Article
Optics
Ivan Supic, Nicolas Brunner
Summary: This study demonstrates that measurements exhibiting nonlocality without entanglement can be certified in a device-independent manner. The research also shows that genuine network quantum nonlocality can be obtained using only nonentangled measurements.
Article
Quantum Science & Technology
Ernest Y. -Z. Tan, Pavel Sekatski, Rene Schwonnek, Renato Renner, Nicolas Sangouard, Charles C. -W. Lim
Summary: The security of finite-length keys is crucial for the implementation of DIQKD. This study presents a general finite-size security proof that can be applied to various DIQKD protocols and achieves positive asymptotic keyrates exceeding previous noise thresholds.
Article
Optics
Ivan Supic, Jean-Daniel Bancal, Yu Cai, Nicolas Brunner
Summary: The network structure allows for the existence of novel forms of quantum nonlocal correlations that cannot be explained by standard quantum Bell nonlocality. We introduce the concept of genuine network quantum nonlocality and demonstrate its operational approach that views standard quantum nonlocality as a resource for producing correlations in networks. By considering the bilocality network of entanglement swapping, we present examples of genuine network nonlocal correlations, including an example of quantum self-testing that relies on the network structure.
Article
Optics
Jean-Daniel Bancal, Nicolas Gisin
Summary: Nonlocal boxes are conceptual tools that capture the essence of quantum nonlocality phenomenon. Specifically tailored for quantum networks, these boxes are essentially unique under the natural assumption of connecting independent sources and without signaling allowed.
Article
Optics
Yu Cai, Baichu Yu, Pooja Jayachandran, Nicolas Brunner, Valerio Scarani, Jean-Daniel Bancal
Summary: This work introduces the concept of absolutely entangled sets of quantum states, where at least one state in the set is entangled for any global basis. A quantitative measure for absolute set entanglement is proposed, with a method based on polynomial optimization to perform convex optimization over unitaries for lower bounding this quantity.
Article
Quantum Science & Technology
Sebastian Wagner, Jean-Daniel Bancal, Nicolas Sangouard, Pavel Sekatski
Article
Quantum Science & Technology
Xavier Valcarce, Pavel Sekatski, Davide Orsucci, Enky Oudot, Jean-Daniel Bancal, Nicolas Sangouard
Article
Quantum Science & Technology
Davide Orsucci, Jean-Daniel Bancal, Nicolas Sangouard, Pavel Sekatski