Article
Quantum Science & Technology
Beata Zjawin, David Schmid, Matty J. Hoban, Ana Belen Sainz
Summary: Einstein-Podolsky-Rosen (EPR) steering can be explained by Alice updating her knowledge of Bob's system through measurements on a correlated system, rather than having a causal influence on Bob's system. We propose a resource-theoretic treatment of correlations in EPR scenarios, where local operations and shared randomness (LOSR) are considered as free operations. We show that resource conversion under free operations can be solved using a single instance of a semidefinite program, and we find interesting properties in the pre-order structure of resources.
Article
Physics, Multidisciplinary
Tamoghna Das, Marcin Karczewski, Antonio Mandarino, Marcin Markiewicz, Bianka Woloncewicz, Marek Zukowski
Summary: In this article, we discuss the interferometric scheme proposed by Tan, Walls, and Collett (TWC) that claims to reveal the Bell non-classicality of a single photon. We demonstrate that the violation of local realism reported by TWC relies on an additional assumption about hidden variables. Without this assumption, it is possible to construct a classical model that accurately predicts all the probabilities of the TWC scheme. We present a proper Bell inequality that does not require additional assumptions and is not violated by the TWC setup. Additionally, we propose a modification of the interferometric scheme by making the amplitude of auxiliary fields tunable, which enables Bell violation. Finally, we provide an alternative perspective on the shortcomings of the original TWC analysis, arguing that it treats weak coherent states as classical.
Article
Physics, Multidisciplinary
Yue Zhang, Shunlong Luo
Summary: The article introduces a method to quantify the nonclassicality of multimode bosonic field states using an information-theoretic approach, and illustrates the fundamental properties and some applications of this quantifier. Various extensions are also mentioned for further exploration.
COMMUNICATIONS IN THEORETICAL PHYSICS
(2021)
Article
Astronomy & Astrophysics
Adrian Kent, Damian Pitalua-Garcia
Summary: The BMV experiment aims to prove that spacetime is nonclassical by observing entanglement generated by gravity, but local hidden variable theories can simulate this entanglement. By extending the entanglement from the BMV experiment to distant quantum particles in a Bell experiment, violating a Bell inequality would rule out LHVTs, providing stronger evidence for the nonclassicality of spacetime.
Article
Quantum Science & Technology
Si-ren Yang, Chang-shui Yu
Summary: In this paper, we investigate how to quantify dynamical quantum resources in the resource non-increasing framework, presenting two methods: distance measures and maximal increasing static resource. Using the quantification of dynamical total coherence as a demonstration, the distance-based measures are shown to have good operational interpretation and can be numerically calculated through semidefinite programming, while measures based on the maximal increasing static resource lead to analytical solutions.
QUANTUM INFORMATION PROCESSING
(2022)
Article
Physics, Multidisciplinary
Deng-Hui Yu, Chang-Shui Yu
Summary: We establish entanglement monotones in terms of an operational approach, showing that any good entanglement quantifier defined on pure states can induce an entanglement monotone for all density matrices, with our proposed monotone being the maximum among those with the same form in pure states. In certain special cases, our proposed entanglement monotones are equivalent to the convex roof construction, giving them an operational meaning.
Article
Physics, Multidisciplinary
Teiko Heinosaari, Leevi Leppajarvi
Summary: Random Access Tests (RATs) are a natural generalization of Random Access Codes (RACs) and are defined for any finite collection of measurements in an arbitrary finite dimensional general probabilistic theory. RATs can be used to examine collective properties of collections of measurements, and the violation of a classical bound in a RAT is a signature of either measurement incompatibility or super information storability.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2022)
Article
Multidisciplinary Sciences
Christopher W. Lynn, Danielle S. Bassett
Summary: By modeling networks as information sources and compressing them using rate-distortion theory, the study investigates the compressibility and characteristics of networks. The results show that compressibility is positively correlated with the transitivity and degree heterogeneity of the networks.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Computer Science, Theory & Methods
P. Gillibert, T. Lachmann, C. Muellner
Summary: This paper demonstrates that the VC-dimension of the family of d-dimensional axis-parallel boxes and cubes on the d-dimensional torus is asymptotically d log(2) d, which is different from most other examples where the VC-dimension usually grows linearly with d in similar settings.
JOURNAL OF COMPLEXITY
(2022)
Article
Environmental Studies
Sattar Salimian, Siab Mamipour, Salah Salimian
Summary: Oil and gas play a crucial role in economic growth and development, driving economic and productive activities. This study examines the strategic approaches of Iran and Qatar in the exploitation of their shared gas field. The findings suggest that extraction power influenced by international sanctions determines a country's decision to cooperate or not. Due to Iran's sanctions and decreased extraction power, it adopts a cooperative strategy, while Qatar's dominant approach is non-cooperation.
Article
Astronomy & Astrophysics
David Dudal, Philipe De Fabritiis, Marcelo S. Guimaraes, Itzhak Roditi, Silvio P. Sorella
Summary: In this paper, we propose a general setup to investigate the violation of the Bell-Clauser-Horne-Shimony-Holt (Bell-CHSH) inequality in the vacuum state in the context of quantum field theory. By constructing specific test functions and satisfying relativistic causality requirements, we report violations of the Bell-CHSH inequality as close as desired to Tsirelson's bound.
Article
Biodiversity Conservation
Huishang She, Zhiyong Jiang, Gang Song, Per G. P. Ericson, Xu Luo, Shimiao Shao, Fumin Lei, Yanhua Qu
Summary: This study investigated the adaptive divergence of three sympatric snowfinches, finding significant phenotypic differences, particularly in body and beak sizes. The research also revealed that adaptive divergence is mainly constrained by developmental genes, and the genetic divergence is closely correlated with differences in niche and food resources segregation-related traits.
DIVERSITY AND DISTRIBUTIONS
(2022)
Article
Physics, Multidisciplinary
Alfonso Delgado-Bonal, Alvaro Garcia Lopez
Summary: Currency markets are international networks open all day without supervision, where the value is determined by central bank decisions and speculator behavior. This study quantitatively analyzes the impact of decisions on system complexity and predictability, showing that forex market is more predictable on an hourly scale and variance is easier to predict for longer time frames.
PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS
(2021)
Article
Quantum Science & Technology
M. M. Taddei, T. L. Silva, R. Nery, G. H. Aguilar, S. P. Walborn, L. Aolita
Summary: The study finds that there may be a contradictory effect in the standard definition of multipartite steering, where entanglement can be created in the system through local operations but has not been experimentally confirmed. By redefining this concept, operational consistency is reestablished, and hidden entanglement properties are revealed. In addition, there are protocols that can reveal entanglement and Bell nonlocality in seemingly unsteerable systems.
NPJ QUANTUM INFORMATION
(2021)
Article
Computer Science, Artificial Intelligence
Siqi Qiu, Xinguo Ming
Summary: This paper proposes Valuation-Based System methods to model systems subject to common-cause failures, considering parametric uncertainty and model uncertainty. Both methods are suitable for modeling systems subject to common-cause failures under different kinds of uncertainties.
KNOWLEDGE-BASED SYSTEMS
(2021)
Article
Quantum Science & Technology
Mehul Malik, Elizabeth Agudelo, Ravi Kunjwal
Summary: Strict global immigration policies and the COVID-19 pandemic have created significant hurdles for the mobility of researchers, especially quantum researchers. High visa fees, difficulties in navigating foreign immigration systems, lack of family support, and targeted government policies have severely impacted their ability to cross physical and scientific borders. Implementing good practices on governmental, institutional, and societal levels can help overcome these challenges and ensure that quantum scientists can achieve their fullest potential.
QUANTUM SCIENCE AND TECHNOLOGY
(2022)
Article
Physics, Multidisciplinary
David Schmid, Haoxing Du, John H. Selby, Matthew F. Pusey
Summary: This study provides a complete characterization of the (non)classicality of all stabilizer subtheories. It proves that there is a unique nonnegative and diagram-preserving quasiprobability representation of the stabilizer subtheory in all odd dimensions, known as Gross's discrete Wigner function. This representation is equivalent to Spekkens' epistemically restricted toy theory, establishing it as the unique noncontextual ontological model for the stabilizer subtheory. On the other hand, in all even dimensions, it is shown that there does not exist any nonnegative and diagram-preserving quasiprobability representation of the stabilizer subtheory, indicating its contextual nature.
PHYSICAL REVIEW LETTERS
(2022)
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
Lorenzo Catani, Matthew Leifer, Giovanni Scala, David Schmid, Robert W. Spekkens
Summary: Uncertainty relations limit the extent to which the outcomes of measurements on a single state can be jointly predictable. While there are some uncertainty relations that are consistent with the classical worldview to some extent, there are still aspects that cannot be realized in this way and constitute genuine nonclassicality. This article investigates the predictability tradeoff of binary-outcome measurements and shows that for certain theories, the functional form of this tradeoff is constrained by noncontextuality. Qubit quantum theory violates this constraint, indicating the presence of contextuality. The implications for operational foils to quantum theory and the generalization to three measurements are also discussed.
PHYSICAL REVIEW LETTERS
(2022)
Article
Quantum Science & Technology
Victoria J. Wright, Ravi Kunjwal
Summary: The Kochen-Specker theorem shows the nonclassicality of single quantum systems, while Bell's theorem and entanglement concern the nonclassicality of composite quantum systems. However, for multiqubit systems, both entanglement and non-locality are essential to proving the Kochen-Specker theorem.
Article
Physics, Multidisciplinary
John H. Selby, David Schmid, Elie Wolfe, Ana Belen Sainz, Ravi Kunjwal, Robert W. Spekkens
Summary: Incompatible measurements are often seen as a characteristic of quantum theory that distinguishes it from classical worldviews. However, a more general notion of classicality is the existence of a generalized-noncontextual ontological model. This notion can imply constraints on the representation of outcomes even within a single nonprojective measurement. We demonstrate that measurement incompatibility is not necessary nor sufficient for proofs of the failure of generalized noncontextuality, and that every proof of the failure of generalized noncontextuality can be converted into a corresponding scenario without incompatible measurements.
PHYSICAL REVIEW LETTERS
(2023)
Article
Multidisciplinary Sciences
Emanuele Polino, Davide Poderini, Giovanni Rodari, Iris Agresti, Alessia Suprano, Gonzalo Carvacho, Elie Wolfe, Askery Canabarro, George Moreno, Giorgio Milani, Robert W. Spekkens, Rafael Chaves, Fabio Sciarrino
Summary: The authors realize a photonic experiment to demonstrate a triangle causal structure, which violates classical predictions without external inputs. The violation of Bell inequalities can only be explained by modeling causal dependencies as intrinsically quantum. There are also other causal structures beyond Bell that can witness nonclassicality, some of which do not require external inputs.
NATURE COMMUNICATIONS
(2023)
Article
Optics
John H. Selby, David Schmid, Elie Wolfe, Ana Belen Sainz, Ravi Kunjwal, Robert W. Spekkens
Summary: The formalism of generalized probabilistic theories (GPTs) was developed to characterize conceivable physical theories. The GPT describing a specific physical theory includes all possible processes. This study introduces an accessible GPT fragment to describe the characteristics of a particular experimental setup within a physical theory. Cone equivalence is defined as an equivalence relation between accessible GPT fragments. Several examples are given to demonstrate the use of accessible GPT fragments in experimental scenarios, and it is proven that failures of generalized noncontextuality can be witnessed without incompatibility among measurements or the assumption of freedom of choice.
Article
Quantum Science & Technology
Shiv Akshar Yadavalli, Ravi Kunjwal
Summary: This paper investigates the entanglement-assisted one-shot classical communication problem. It shows that entanglement can increase the one-shot zero-error capacity in the zero-error regime but not in the presence of noise or measurements. By examining the one-shot success probability of sending a fixed number of classical messages, the paper demonstrates that preparation contextuality can enhance the success probability. Additionally, a mapping between this communication task and a corresponding nonlocal game is established.
Article
Quantum Science & Technology
Alessia Suprano, Davide Poderini, Emanuele Polino, Iris Agresti, Gonzalo Carvacho, Askery Canabarro, Elie Wolfe, Rafael Chaves, Fabio Sciarrino
Summary: Quantum networks play a vital role in quantum science, leading to discoveries in quantum theory and enabling innovative communication and cryptography protocols. This article verifies the nonlocality of an experimental triangle network composed of three independent sources of entangled photons.
Article
Optics
Michael J. Grabowecky, Christopher A. J. Pollack, Andrew R. Cameron, Robert W. Spekkens, Kevin J. Resch
Summary: Researchers implemented GPT tomography on a three-level quantum system using the framework of generalized probabilistic theories (GPTs), allowing theory-agnostic analysis of experimental data. The analysis identified the most likely dimension of the GPT vector space describing the system to be nine, consistent with quantum theory predictions. Additionally, quantitative bounds on possible deviations from quantum theory were determined by identifying polytopes that bounded the state and effect spaces of the true GPT.
Article
Quantum Science & Technology
Rafael Chaves, George Moreno, Emanuele Polino, Davide Poderini, Iris Agresti, Alessia Suprano, Mariana R. Barros, Gonzalo Carvacho, Elie Wolfe, Askery Canabarro, Robert W. Spekkens, Fabio Sciarrino
Summary: Bell's theorem proves the incompatibility between quantum theory and local hidden-variable models, showing that classical causal models cannot explain quantum correlations, but measurement dependence can be quantitatively upper bounded within a network.
Article
Quantum Science & Technology
David Schmid, John H. Selby, Elie Wolfe, Ravi Kunjwal, Robert W. Spekkens
Summary: This study explores the notion of classicality in generalized probabilistic theory (GPT) and introduces the concept of simplex embeddability as a geometric condition for classicality in GPT. In essence, simplex embeddability requires the state space of a GPT to be embeddable in a simplex and its effect space in the dual of that simplex, providing a new intuitive and standalone notion of classicality for GPTs.