Local Description Research Articles

Scattering amplitudes for monopoles: pairwise little group and pairwise helicity

On-shell methods are particularly suited for exploring the scattering of electrically and magnetically charged objects, for which there is no local and Lorentz invariant Lagrangian description. In this paper we show how to construct a Lorentz-invariant S-matrix for the scattering of electrically and magnetically charged particles, without ever having to refer to a Dirac string. A key ingredient is a revision of our fundamental understanding of multi-particle representations of the Poincaré group. Surprisingly, the asymptotic states for electric-magnetic scattering transform with an additional little group phase, associated with pairs of electrically and magnetically charged particles. The corresponding “pairwise helicity” is identified with the quantized “cross product” of charges, e1g2− e2g1, for every charge-monopole pair, and represents the extra angular momentum stored in the asymptotic electromagnetic field. We define a new kind of pairwise spinor-helicity variable, which serves as an additional building block for electric-magnetic scattering amplitudes. We then construct the most general 3-point S-matrix elements, as well as the full partial wave decomposition for the 2 → 2 fermion-monopole S-matrix. In particular, we derive the famous helicity flip in the lowest partial wave as a simple consequence of a generalized spin-helicity selection rule, as well as the full angular dependence for the higher partial waves. Our construction provides a significant new achievement for the on-shell program, succeeding where the Lagrangian description has so far failed.

On the use of effective thermophysical properties to predict the melting process of composite phase change materials with coarse structures

Composite PCMs combining metallic foam and paraffin are widely used as phase change materials (PCMs) to tailor the properties of pure PCMs and enhance the thermal energy storage/release. For the complex composites structures, the transient thermal response prediction by direct simulation (DS) is not easy in term of geometry generation and computation. The volume-averaged model (1T model) considering the composite PCMs as homogeneous media is sometimes used to deal with thermal transport in Composite PCMs, not always with a sufficiently good local description of non-steady conditions. The paper carries out a set of cases where a composite PCM modelled as an open-pore body-centred cell made of Aluminium (Al) filled with paraffin (i) to investigate the combined effects of the geometry of the unit cell (side length, porosity), the composite sample (sample height) and boundary conditions (heat input) on the heat response; (ii) to identify the local/overall errors in temperature and volume fraction of liquid PCM (and thus of stored heat) induced by the use of 1T model for various geometry/heat flux combinations. Analytical equations are proposed to predict the maximum temperature difference between Al and PCM as well as the maximum temperature difference calculated by applying the 1T or DS model as a function of the open cell structure geometry and heat flux. The main novelty introduced in the paper is the analytical model used to quantify the maximum local error on molten PCM volume fraction for the 1T model, and thus on heat stored/released. The model supplies good local thermal response predictions for fine structures and lower heat flux input. Nevertheless, errors in the volume fraction of molten PCMs predicted for the whole sample are far lower and the 1T model can be easily applied in a wider range of geometry/conditions.

Locality and General Vacua in Quantum Field Theory

We extend the framework of general boundary quantum field theory (GBQFT) to achieve a fully local description of realistic quantum field theories. This requires the quantization of non-Kähler polarizations which occur generically on timelike hypersurfaces in Lorentzian spacetimes as has been shown recently. We achieve this in two ways: On the one hand we replace Hilbert space states by observables localized on hypersurfaces, in the spirit of algebraic quantum field theory. On the other hand we apply the GNS construction to twisted star-structures to obtain Hilbert spaces, motivated by the notion of reflection positivity of the Euclidean approach to quantum field theory. As one consequence, the well-known representation of a vacuum state in terms of a sea of particle pairs in the Hilbert space of another vacuum admits a vast generalization to non-Kähler vacua, particularly relevant on timelike hypersurfaces.

Single-copy activation of Bell nonlocality via broadcasting of quantum states

Activation of Bell nonlocality refers to the phenomenon that some entangled mixed states that admit a local hidden variable model in the standard Bell scenario nevertheless reveal their nonlocal nature in more exotic measurement scenarios. We present such a scenario that involves broadcasting the local subsystems of a single-copy of a bipartite quantum state to multiple parties, and use the scenario to study the nonlocal properties of the two-qubit isotropic state:ρα=α|Φ+⟩⟨Φ+|+(1−α)14.We present two main results, considering that Nature allows for (i) the most general no-signalling correlations, and (ii) the most general quantum correlations at the level of any hidden variable theory. We show that the state does not admit a local hidden variable description for α>0.559 and α>12, in cases (i) and (ii) respectively, which in both cases provides a device-independent certification of the entanglement of the state. These bounds are significantly lower than the previously best-known bound of 0.697 for both Bell nonlocality and device-independent entanglement certification using a single copy of the state. Our results show that strong examples of non-classicality are possible with a small number of resources.

Intercalation of N-methylformamide in kaolinite: In situ monitoring by near-infrared spectroscopy and X-ray diffraction

The selective self-assembly of small molecules in the interlayer of kaolinite is a fundamentally important and technologically relevant process, typically studied ex situ by X-ray diffraction (XRD). Near-infrared (NIR) spectroscopy is now introduced to provide a complementary local structural description of intercalation with improved control of experimental conditions.New NIR- and XRD-based proxies were developed and applied to the real-time monitoring of N-methylformamide (NMF) intercalation in two reference kaolinites differing in stacking order.The commonly employed XRD-based formalism was found to overestimate reaction progress. The bonding of NMF in the interlayer was independent of reaction progress and kaolinite type. Both NIR and XRD recorded identical sigmoidal kinetics. Isothermal NIR monitoring (25–80 °C) yielded time-temperature superimposable sigmoidals with an apparent activation energy of ~60 kJ/mol, common to both samples. All NIR and XRD data series could be described as linear combinations of empty and fully intercalated kaolinite. The filling of the interlayer was too fast to be observed. The sigmoidal curves were instead modeled as the log-normally distributed response of an ensemble of intercalating entities, presumably crystallites. The multiplicative standard deviation of the distribution, which determines its steepness, is a sample-specific, temperature-independent property of kaolinite.

Identification of the agroclimatic suitability in the municipality of Fusagasuga (Cundinamarca) for pea crop (Pisum sativum L.), using participatory mapping

Pea crop is highly vulnerable to the negative impacts of variability and climate change, due to its socioeconomic and environmental marginality, as well as the poor use of technical tools such as agroclimatic information. Therefore, in order to understand the local pea growers perception of agroclimatic risk, a participatory mapping experience implemented in the rural area of the municipality of Fusagasuga was performed. Edaphoclimatic constraints and opportunities of the Municipality for pea crop were identified. The exercise started with the dissemination of local climatic data and thematic cartography related to biophysical variables like elevation and slope. Local descriptions of soil characteristics were defined with the community to identify areas with the most and the least limiting soil conditions for pea crop. In addition, the areas with greater susceptibility to water deficit and water excess were identified. The paper emphasizes on the methodological and pedagogical process generated for the identification of agroclimatic risks. The results show how participatory learning empowers communities with information to improve their own knowledge of the territory. This approach contributes to the adaptative capacity to extreme weather events since it provides elements for community organization to face risk. The participatory approach allowed the identification of Aguadita, Bermejal, Tierranegra, La Palma, Bochica, Batan, Santa Lucía, El Guavio y El Carmen as low-risk areas for pea production due to their soil advantages and low occurrence of water deficit and water excess events.

The speckled ground squirrel (Spermophilus suslicus) in Belarus: new localities, old threats, and prospects of conservation

The study was carried out as part of the project "Superrodent" and is devoted to the description of new record localities of the spotted ground squirrel (Spermophilus suslicus s. l.) discovered by the authors during 2019–2020. It is one of the rarest species of rodents and mammals in the fauna of Belarus in general. This species suffers from anthropogenic changes in the environment and its agricultural development and to ensure its protection it is listed in a number of ‘red lists’, including the IUCN Red List and the Red Book of the Republic of Belarus (since 2015). The search for ground squirrel habitats was carried out in two stages. The first included the analysis of the literature on already known localities and biotope preferences, including cartographic data to identify promising areas to search for. The second stage provides a direct survey of prospective sites, their photo documentation and a detailed description. In total, nine new habitats of the species were identified within four administrative districts of Minsk Oblast of Belarus: Nesvizh Raion (4), Stowbtsy Raion (1), Baranivka Raion (1) and Kapyl Raion (2). In addition, an inspection of the sites previously identified by the authors revealed that some of them have already disappeared or are in critical state, the reason for which is primarily the land ploughing. In fact, today there are only six viable suslik settlements in Belarus. All of them are confined to elevated areas of the Kopyl ridge, which is located in the northern part of the Continental biogeographic region. Most of the surviving colonies are not large and consist of a few dozen to 150 living burrows. The number of the only large colony (Yushevichi) is estimated at 10 to 11 thousand individuals. All other inhabited colonies are located at a distance as far as 6 km from the Yushevichi colony. In other regions of Belarus, despite searches, ground squirrels are currently not found. The key threats to the species' existence are the ploughing of colonies and the overgrowth of tall grasses and trees and shrubs. In our opinion, for the long-term preservation of the species in the country, it is necessary to establish an appropriate protection regime (management), as well as the implementation of comprehensive monitoring: monitoring of threats, successions of plant communities, and the state of ground squirrel populations. Suggestions for protection and further monitoring of locations are given. Among other initiatives, the authors sent proposals to local authorities on granting protection status to areas with settlements of ground squirrels.

Derivation of a macroscopic mixture model for two-phase turbulent flows

This article addresses the issue of reduced models to describe turbulent two-phase flows in industrial applications. A spatially-averaged mixture or drift-flux model is derived theoretically from the local instantaneous Navier-Stokes description. Reynolds-averaging and space-averaging are applied successively. Between these two steps, a model reduction is achieved to account for the non-equilibrium between phases via algebraic relations. Applications of this work are not limited to porous media but also include macroscopic descriptions to model high-shear regions developing near the walls for internal flows. Thermal effects, heat transfer at the wall and phase-change are also considered and briefly discussed. The final model describes the evolution of mixture variables, including effects of both sub-filter spatial variations, turbulence, and local non-equilibrium in velocity, pressure and enthalpy. This analysis provides bridges between different approaches to model two-phase flows (local instantaneous description, two-fluid model, local drift-flux model and spatially-averaged drift-flux model). It clarifies the content of each model involved by defining them in terms of local instantaneous quantities. Turbulent fluctuations and phase intermittency are crucial mechanisms. Important effects to model also include void fraction dispersion and turbulent diffusion; then, it is necessary to model the relative velocity, including the drift velocity orthogonal to gravity induced by the complex interactions between turbulent velocity fluctuations and the interfacial momentum transfer.The final macroscopic (spatially-averaged) mixture formulation is open, in the sense that expressions to model the various terms representing the physics of the small scales are not provided; instead, the physical sense and the origin of these models are discussed. The paper is meant as a basis on which analyses on local imbalance assumptions or relative velocity closures can be assessed. CFD simulations can provide information to complement experiments in technically challenging physical conditions or on processes essential to the models yet difficult to access experimentally (such as interfacial transfers for instance). Different kinds of two-fluid models can be tested to analyse their consequences on the macroscopic spatially-averaged model. In addition, a new path to calibrate closure laws or propose new models is opened based on finer-scale descriptions. Guidelines to use fine simulations along with the open expressions to derive closure relations either for the local drift-flux or for the spatially-averaged models are presented. They concern the modelling of the local relative velocity, the spatial average of the diffusion of void fraction and of the pressure drop.

О плотности многочленов в специальном пространстве целых функций экспоненциального типа

The traditional approach to solving a specific problem of spectral synthesis in a complex domain involves reducing it to the problem of local description of closed submodules in a certain space of entire functions. The last problem is split into checking the stability and saturation of the submodule under study. This approach turned out to be very effective, for example, in the study of submodules of local rank 1 and in the study of submodules in topological modules associated with unbounded convex domains. Recent studies on spectral synthesis in the complex domain are based on a different scheme. This scheme involves reducing the problem of local description to checking the density of polynomials in a special module of entire functions of exponential type. Moreover, the space under study is a separable locally convex space of type (LN)*. Polynomial approximation in such a space is understood by us as sequential approximation, that is, we are talking about the approximation of space elements by ordinary (not generalized) sequences of polynomials. In this article, we study a special locally convex module of entire vector functions over the ring of polynomials in the degree of the independent variable. The theorem proved in the article can serve as a source of new results on spectral synthesis in the complex domain.

A lithofacies analysis of a South Polar glaciation in the Early Permian: Pagoda Formation, Shackleton Glacier region, Antarctica

ABSTRACTThe currently favored hypothesis for Late Paleozoic Ice Age glaciations is that multiple ice centers were distributed across Gondwana and that these ice centers grew and shank asynchronously. Recent work has suggested that the Transantarctic Basin has glaciogenic deposits and erosional features from two different ice centers, one centered on the Antarctic Craton and another located over Marie Byrd Land. To work towards an understanding of LPIA glaciation that can be tied to global trends, these successions must be understood on a local level before they can be correlated to basinal, regional, or global patterns. This study evaluates the sedimentology, stratigraphy, and flow directions of the glaciogenic, Asselian–Sakmarian (Early Permian) Pagoda Formation from four localities in the Shackleton Glacier region of the Transantarctic Basin to characterize Late Paleozoic Ice Age glaciation in a South Polar, basin-marginal setting. These analyses show that the massive, sandy, clast-poor diamictites of the Pagoda Fm were deposited in a basin-marginal subaqueous setting through a variety of glaciogenic and glacially influenced mechanisms in a depositional environment with depths below normal wave base. Current-transported sands and stratified diamictites that occur at the top of the Pagoda Fm were deposited as part of grounding-line fan systems. Up to at least 100 m of topographic relief on the erosional surface underlying the Pagoda Fm strongly influenced the thickness and transport directions in the Pagoda Fm. Uniform subglacial striae orientations across 100 m of paleotopographic relief suggest that the glacier was significantly thick to “overtop” the paleotopography in the Shackleton Glacier region. This pattern suggests that the glacier was likely not alpine, but rather an ice cap or ice sheet. The greater part of the Pagoda Fm in the Shackleton Glacier region was deposited during a single retreat phase. This retreat phase is represented by a single glacial depositional sequence that is characteristic of a glacier with a temperate or mild subpolar thermal regime and significant meltwater discharge. The position of the glacier margin likely experienced minor fluctuations (readvances) during this retreat. Though the sediment in the Shackleton Glacier region was deposited during a single glacier retreat phase, evidence from this study does not preclude earlier or later glacier advance–retreat cycles preserved elsewhere in the basin. Ice flow directions indicate that the glacier responsible for this sedimentation was likely flowing off of an upland on the side of the Transantarctic Basin closer to the Panthalassan–Gondwanide margin (Marie Byrd Land), which supports the hypothesis that two different ice centers contributed glaciogenic sediments to the Transantarctic Basin. Together, these observations and interpretations provide a detailed local description of Asselian–Sakmarian glaciation in a South Polar setting that can be used to understand larger-scale patterns of regional and global climate change during the Late Paleozoic Ice Age.

Dynamic localization of DNA topoisomerase I and its functional relevance during Drosophila development.

DNA topoisomerase I (Top1) maintains chromatin conformation during transcription. While Top1 is not essential in simple eukaryotic organisms such as yeast, it is required for the development of multicellular organisms. In fact, tissue and cell-type-specific functions of Top1 have been suggested in the fruit fly Drosophila. A better understanding of Top1’s function in the context of development is important as Top1 inhibitors are among the most widely used anticancer drugs. As a step toward such a better understanding, we studied its localization in live cells of Drosophila. Consistent with prior results, Top1 is highly enriched at the nucleolus in transcriptionally active polyploid cells, and this enrichment responds to perturbation of transcription. In diploid cells, we uncovered evidence for Top1 foci formation at genomic regions not limited to the active rDNA locus, suggestive of novel regulation of Top1 recruitment. In the male germline, Top1 is highly enriched at the paired rDNA loci on sex chromosomes suggesting that it might participate in regulating their segregation during meiosis. Results from RNAi-mediated Top1 knockdown lend support to this hypothesis. Our study has provided one of the most comprehensive descriptions of Top1 localization during animal development.

Comprehensive Analysis of Heat and Water Exchanges in the Human Lungs.

This work presents a new mathematical model of the heat and water exchanges in the human lungs (newborn to adult). This model is based on a local description of the water and energy transports in both the lumen and the surrounding tissues, and is presented in a comprehensive, dimensionless framework with explicitly stated assumptions and a strong physiological background. The model is first used to analyze and quantify the key phenomena and dimensionless numbers governing these heat and water exchanges and then it is applied to an adult in various situations (varying atmospheric conditions, exercising…). The results highlight several interesting physiological elements. They show that the bronchial region of the lungs is able to condition the air in all the considered situations even if, sometimes, for instance when exercising, distal generations have to be involved. The model also shows that these distal generations are super-conditioners. Moreover, the results quantify the key role of the submucosal glands in mucus hydration. They also show that, during expiration, a significant cooling of the air and condensation of water occur along the respiratory tract as the vascularization of the tissues surrounding the airways is not able to maintain these tissues at body temperature during inspiration. Due to the interaction between several phenomena, it appears that the ratio of the amount of water returned to the mucosa during expiration to the amount extracted during inspiration is almost independent of the breathing conditions (around 33%). The results also show that, in acute situations, such as suffering from a pathology with airway dysfunction, when being intubated or when exercising above an intensity threshold, the heat and water exchanges in the lungs may be critical regarding mucus hydration. In proximal generations, the evaporation may overwhelm the ability of the submucosal glands to replenish the airway surface liquid with water. In some situations, the cooling of the mucosa may be very important; it can even become colder than the inspired air, due to evaporative cooling. Finally, the results show that breathing cold air can significantly increase the exchanges between the lungs and the environment, which can be critical regarding disease transmission.

Non local effects in cone-shaped metamaterials

Light-matter interactions in a material may be dramatically influenced by the features of the medium. Moreover, the electromagnetic characteristics of the material in the nearby areas may make a dramatic impact as well. Following the first scenario, the medium is considered to be local, whereas in the other case, it is nonlocal. It has been demonstrated by the current works on light-matter interactions in composites that novel optical phenomena is enabled by nonlocal effects. The former can not be treated in case of local effective medium description.

A retrospective analysis of emerging rabies: a neglected tropical disease in Sarawak, Malaysia.

Rabies, a neglected tropical disease (NTD), is a viral infection which is often fatal. Since 2017, a rabies epidemic has been declared in Sarawak, Malaysia. However, there is a lack of local epidemiological data and descriptions of local presentations of this disease. This was a retrospective analysis of a series of rabies cases encountered in Sibu Hospital, Sarawak from March 2020 to February 2021. Six cases of rabies were identified in this series, all with a mixture of upper motor neuron and lower motor neuron findings. Most cases did not seek medical attention upon dog bite and therefore effective post-exposure prophylaxis was not given. The incubation period varied from 17 days to 2 years. All cases died, with five cases succumbing to the illness within two weeks of symptom onset. The cumulative incidence for rabies in Sibu was estimated at 1.7 per 100,000 population. The lack of public awareness of the implication of animal bites and the immediate management in rabies-endemic regions are factors contributing to high rabies mortality.

Synergistic foam stabilization and transport improvement in simulated fractures with polyelectrolyte complex nanoparticles: Microscale observation using laser etched glass micromodels

Inaccessibility to direct pore scale observation in hydrocarbon recovery of tight shale formations poses a great challenge to water-energy nexus initiatives and necessitates the use of high throughput technologies to emulate environmentally friendly processes. Herein, we employ a precise glass micromodel fabrication and visualization method to isolate the supercritical CO2 bubbles surrounded by CO2-water lamella prepared in saline produced water stabilized with molecular complexation of zwitterionic surfactants (ZS) and polyelectrolyte complex nanoparticles (PECNP).The Selective Laser Enhanced Etching (SLE) technique was selected for micromodel simulation of high-pressure flow. Two representative designs, (1) fracture/micro-crack network and (2) fracture/matrix were etched on fused silica glass with a laser printing machine and scCO2 foam was injected to study the foamability, propagation, stability, and fluid loss properties.The highly monodispersed and uniformly distributed array of scCO2 bubbles were detected in flow of scCO2 foam in highly saline brine containing ionic complexes of positively charged PECNPs and ZS, whereas foam flow with the lamella containing ZS in fractures offered a noticeably large and polydisperse array of scCO2 bubbles. scCO2 bubble motion and deformation were traced, and local description of foam flow was visually examined. The confined array of scCO2 bubbles stabilized by ZS in microcracks was affected by bubble growth and coalescence, whereas the super-populated array of monodispersed scCO2 bubbles with lamella containing complexes of PECNP and ZS were able to fill the channels with stable configurations within the timeframe of comparative stability measurements. The ability of complex fluid to prevent the formation damage was evaluated through fluid loss visualization in micromodels. Probing scCO2 foam transport in homogenous porous media revealed smaller volume leak-off for scCO2 foam containing PECNP-ZS ionic complexes.

Steering paradox for Einstein–Podolsky–Rosen argument and its extended inequality

The Einstein–Podolsky–Rosen (EPR) paradox is one of the milestones in quantum foundations, arising from the lack of a local realistic description of quantum mechanics. The EPR paradox has stimulated an important concept of “quantum nonlocality,” which manifests itself in three types: quantum entanglement, quantum steering, and Bell’s nonlocality. Although Bell’s nonlocality is more often used to show “quantum nonlocality,” the original EPR paradox is essentially a steering paradox. In this work, we formulate the original EPR steering paradox into a contradiction equality, thus making it amenable to experimental verification. We perform an experimental test of the steering paradox in a two-qubit scenario. Furthermore, by starting from the steering paradox, we generate a generalized linear steering inequality and transform this inequality into a mathematically equivalent form, which is friendlier for experimental implementation, i.e., one may measure the observables only in the x , y , or z axis of the Bloch sphere, rather than other arbitrary directions. We also perform experiments to demonstrate this scheme. Within the experimental errors, the experimental results coincide with theoretical predictions. Our results deepen the understanding of quantum foundations and provide an efficient way to detect the steerability of quantum states.

GraNet: Global relation-aware attentional network for semantic segmentation of ALS point clouds

Semantic labeling is an essential but challenging task when interpreting point clouds of 3D scenes. As a core step for scene interpretation, semantic labeling is the task of annotating every point in the point cloud with a label of semantic meaning, which plays a significant role in plenty of point cloud related applications. For airborne laser scanning (ALS) point clouds, precise annotations can considerably broaden its use in various applications. However, accurate and efficient semantic labeling is still a challenging task, due to the sensor noise, complex object structures, incomplete data, and uneven point densities. In this work, we propose a novel neural network focusing on semantic labeling of ALS point clouds, which investigates the importance of long-range spatial and channel-wise relations and is termed as global relation-aware attentional network (GraNet). GraNet first learns local geometric description and local dependencies using a local spatial discrepancy attention convolution module (LoSDA). In LoSDA, the orientation information, spatial distribution, and elevation information are fully considered by stacking several local spatial geometric learning modules and the local dependencies are learned by using an attention pooling module. Then, a global relation-aware attention module (GRA), consisting of a spatial relation-aware attention module (SRA) and a channel relation-aware attention module (CRA), is presented to further learn attentions from the structural information of a global scope from the relations and enhance high-level features with the long-range dependencies. The aforementioned two important modules are aggregated in the multi-scale network architecture to further consider scale changes in large urban areas. We conducted comprehensive experiments on three ALS point cloud datasets to evaluate the performance of our proposed framework. The results show that our method can achieve higher classification accuracy compared with other commonly used advanced classification methods. For the ISPRS benchmark dataset, our method improves the overall accuracy (OA) to 84.5 % and the average F1 measure (AvgF1) to 73.6 %, which outperforms other baselines. Besides, experiments were conducted using a new ALS point cloud dataset covering highly dense urban areas and a newly published large-scale dataset.

Multi-patch local mesh refinement XIGA based on LR NURBS and Nitsche’s method for crack growth in complex cracked plates

The objective of this article is to simulate crack growth of complex Mindlin–Reissner plates by developing an adaptive multi-patch extended isogeometric analysis (XIGA). Nitsche’s method is used to treat continuity between multi-patches or the coupling of non-conforming meshes, exactly describing the geometry of complex plates. The computational meshes in XIGA are independent of the cracks by introducing some enrichment functions into the displacement approximation based on the partition of unity, thus it is convenient in modeling evolution of crack. The locally refined non-uniform rational B-splines (LR NURBS), which have the properties of local refinement and exact description of geometry, are used to construct geometric model and taken as the shape functions in XIGA. To implement the adaptive local refinement, a method based on recovery technique by Zienkiewicz and Zhu is proposed. Based on the Mindlin–Reissner plate theory, interaction integral method is employed to calculate stress intensity factors (SIFs) and the maximum circumferential stress criterion is used to determine the crack propagation direction. Several numerical examples are carried out to demonstrate the performance of the adaptive multi-patch XIGA for simulating crack growth in complex plates.

Experimental test of the Greenberger\u2013Horne\u2013Zeilinger-type paradoxes in and beyond graph states

The Greenberger–Horne–Zeilinger (GHZ) paradox is an exquisite no-go theorem that shows the sharp contradiction between classical theory and quantum mechanics by ruling out any local realistic description of quantum theory. The investigation of GHZ-type paradoxes has been carried out in a variety of systems and led to fruitful discoveries. However, its range of applicability still remains unknown and a unified construction is yet to be discovered. In this work, we present a unified construction of GHZ-type paradoxes for graph states, and show that the existence of GHZ-type paradox is not limited to graph states. The results have important applications in quantum state verification for graph states, entanglement detection, and construction of GHZ-type steering paradox for mixed states. We perform a photonic experiment to test the GHZ-type paradoxes via measuring the success probability of their corresponding perfect Hardy-type paradoxes, and demonstrate the proposed applications. Our work deepens the comprehension of quantum paradoxes in quantum foundations, and may have applications in a broad spectrum of quantum information tasks.

The ABC of Deutsch–Hayden Descriptors

It has been more than 20 years since Deutsch and Hayden proved the locality of quantum theory, using the Heisenberg picture of quantum computational networks. Of course, locality holds even in the face of entanglement and Bell’s theorem. Today, most researchers in quantum foundations are still convinced not only that a local description of quantum systems has not yet been provided, but that it cannot exist. The main goal of this paper is to address this misconception by re-explaining the descriptor formalism in a hopefully accessible and self-contained way. It is a step-by-step guide to how and why descriptors work. Finally, superdense coding is revisited in the light of descriptors.