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Full waveform inversion based on inequality constraint for cross-hole radar
摘要： Cross-hole radar is an effective method for geophysical exploration of underground geological conditions. Besides cross-hole radar, some geological information can be obtained by other methods, such as preliminary geological survey, geologic drilling and long-distance geophysical prospecting. This information can work as priori information to help interpret cross-hole radar detection data. Full waveform inversion (FWI) is an advanced inversion method for cross-hole radar, having higher resolution than the ray tomography method. However, traditional FWI for cross-hole radar takes less advantage of the prior information. Therefore, the introduction of the priori information into FWI is worthy of in-depth study to improve information and improve the accuracy and stability of FWI. The reasonable value inversion quality. Here we use a special penalty function to impose inequality constraint on the objective function, and then calculate a new update step length value different from the traditional FWI. We use this method to introduce the priori range of weight coefficients is discussed, which can control the strength of inequality constraint. Several inversion examples are designed to validate the effect of this improved FWI method. The inversion examples for synthetic and field data show that FWI based on inequality constraint for cross-hole radar has better inversion effect than the traditional FWI. To a certain extent, the introduction of inequality constraint can constrain inversion process, improve the inversion stability and provide higher precision inversion results.
关键词： Inequality constraint,Inverse theory,Cross-hole radar,Full waveform inversion,Priori information
更新于2025-09-23 15:23:52
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Loophole-Free Bell Tests and the Falsification of Local Realism
摘要： Quantum mechanics is strictly incompatible with local realism. It has been shown by Bell and others that it is possible, in principle, to experimentally differentiate between local realism and quantum mechanics. Numerous experiments have attempted to falsify local realism; however, they have consistently failed to close the detection loophole under strict locality conditions, thereby allowing local realistic explanations for their observations. In 2015, three experiments took place that tested local realism without the impediments of these significant loopholes. Between these three experiments, a substantial data set was collected. All of the collected data show a strong violation of local realism and strong support for quantum mechanics. This article reviews the theoretical basis of Bell tests and the affiliated loopholes, as well as the methods employed by these recent experiments and the implications of the results they observed.
关键词： Local Realism,CHSH Inequality,Loophole-Free Bell Test,CH Inequality,Quantum Mechanics
更新于2025-09-23 15:22:29
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Geometrical self-testing of partially entangled two-qubit states
摘要： Quantum nonlocality has recently been intensively studied in connection to device-independent quantum information processing, where the extremal points of the set of quantum correlations play a crucial role through self-testing. In most protocols, the proofs for self-testing rely on the maximal violation of the Bell inequalities, but there is another known proof based on the geometry of state vectors to self-test a maximally entangled state. We present a geometrical proof in the case of partially entangled states. We show that, when a set of correlators in the simplest Bell scenario satisfies a condition, the geometry of the state vectors is uniquely determined. The realization becomes self-testable when another unitary observable exists on the geometry. Applying this proven fact, we propose self-testing protocols by intentionally adding one more measurement. This geometrical scheme for self-testing is superior in that, by using this as a building block and repeatedly adding measurements, a realization with an arbitrary number of measurements can be self-tested. Besides the application, we also attempt to describe nonlocal correlations by guessing probabilities of distant measurement outcomes. In this description, the quantum set is also convex, and a large class of extremal points is identified by the uniqueness of the geometry.
关键词： device-independent quantum information processing,Bell inequality,quantum nonlocality,self-testing
更新于2025-09-23 15:21:01
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Experimental demonstration of one-sided device-independent self-testing of any pure two-qubit entangled state
摘要： We demonstrate one-sided device-independent self-testing of any pure two-qubit entangled state based on a fine-grained steering inequality. The maximum violation of a fine-grained steering inequality can be used to witness certain steerable correlations, which certify all pure two-qubit entangled states. Our experimental results identify which particular pure two-qubit entangled state has been self-tested and which measurement operators are used on the untrusted side. Furthermore, we analytically derive the robustness bound of our protocol, enabling our subsequent experimental verification of robustness through state tomography. Finally, we ensure that the requisite no-signaling constraints are maintained in the experiment.
关键词： device-independent,two-qubit state,self-testing,steering inequality,quantum entanglement
更新于2025-09-23 15:19:57
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[IEEE 2019 21st International Conference on Transparent Optical Networks (ICTON) - Angers, France (2019.7.9-2019.7.13)] 2019 21st International Conference on Transparent Optical Networks (ICTON) - Plasmonic Waveguides Co-Integrated with Si <sub/>3</sub> N <sub/>4</sub> Waveguide Platform for Integrated Biosensors
摘要： This paper presents a placement algorithm for fault location observability using phasor measurement units (PMUs) in the presence or absence of zero injection buses. The problem is formulated as a binary semidefinite programming (BSDP) model with binary decision variables, minimizing a linear objective function subject to linear matrix inequality (LMI) observability constraints. The model is extended to take into account the unavailability or limited capacity of communication links at some PMU installation buses. The BSDP problem is solved using an outer approximation scheme based on binary integer linear programming. The method is illustrated with a 6-bus test system. Numerical simulations are conducted on the IEEE 14-, 30-, and 57-bus standard test systems to verify the effectiveness of the proposed method.
关键词： semidefinite programming,phasor measurement unit,linear matrix inequality,Fault location observability,synchronized phasor measurements
更新于2025-09-19 17:13:59
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Experimental Violation of Bell's Inequality for Temporal Orders
摘要： Entanglement is a prediction of quantum mechanics that suggests that our physical laws cannot be described by a local causal model. This has led to much debate, including Einstein’s famous suggestion that quantum mechanics is an incomplete theory, and we may one day discover a deeper theory that can be described by a locally causal model. However, loophole free violations of Bell inequalities demonstrate that this is not the case. Bell’s theorem is independent of quantum mechanics, and it shows that any theory attempting to supplant quantum mechanics must be somehow nonlocal. Since then, there have been many experimental violations of Bell inequalities using different physical systems, culminating in three loophole-free experiments [1-3]. Very recent theoretical [4, 5] and experimental techniques [6, 7] have enabled the study of a new phenomenon predicted by quantum mechanics. Namely, the existence of processes without a fixed causal order. Previous experimental tests of this effect, required the assumption that quantum mechanics can be used to correctly model the experimental results. However, just as the study of entanglement before Bell, these results could still be described by some other theory in which the causal order is definite. The question, then, naturally arises do such processes really exist, or are they an artefact of the quantum mechanics. Here we show that these effects are indeed real by constructing a Bell inequality for temporal orders [8]. The violation of this equality implies, independent of quantum mechanics, that the temporal order of the process under study must have been truly indefinite. We then show we can violate this inequality using a system consisting of two quantum SWITCHes [6,7] with entangled control qubits (see Fig. 1).
关键词： quantum mechanics,Bell’s inequality,quantum SWITCH,entanglement,temporal order
更新于2025-09-16 10:30:52
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Time dependent correlations of entangled states with nondegenerate branches and possible experimental realization using singlet fission
摘要： The spin-entangled exciton states produced by singlet fission provide an experimental route to generate entangled states with nondegenerate branches. Nondegenerate entangled pair states possess an internal "clock" that leads to quantum beating in various detected quantities. The implications of this internal clock for Bell’s inequality measurements and correlated particle detection are analyzed using two- and three-state spin models. In a Bell’s inequality experiment, we find that the choice of detection times can determine whether quantum or classical correlations are observed. The conditions under which the detection events could be time- or spacelike separated are analyzed in order to clarify how the temporal evolution of one particle can influence the time-dependent detection probability of the other. Possible routes to the detection of individual correlated triplet excitons are discussed, emphasizing both physical questions concerning the separation and propagation of triplet excitons over macroscopic distances and experimental challenges concerning decoherence, detection, and interpretation of the signals. We argue that spin-entangled triplet exciton states produced by singlet fission could provide a new way to probe entangled state detection and collapse, complementing schemes based on polarization-entangled photon states.
关键词： detection,Bell’s inequality,correlated particle detection,spin-entangled exciton states,nondegenerate branches,triplet excitons,quantum beating,singlet fission,decoherence
更新于2025-09-12 10:27:22
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~3.5 $\mu$ m Er <sup>3+</sup> : ZBLAN Fiber Laser in Dual-End Pumping Regime
摘要： In this paper, a new inner product space is de?ned, which has a standard orthogonal basis. Based on this basis, an improved integral inequality is established, which is used to construct a new Lyapunov–Krasovskii functionals (LKFs). Thus, a less conservative exponential stability criterion of time-delay systems is obtained, which is in form of linear matrix inequalities(LMIs). Finally, non-conservatism of this exponential stability criterion can be not only numerically illustrated by an example, but also rigorously proved in theory.
关键词： Integral inequality,Exponential stability,LMIs,Time-delay systems,Multiple integrals
更新于2025-09-11 14:15:04
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Probing the limits of correlations in an indivisible quantum system
摘要： We employ a trapped ion to study quantum contextual correlations in a single qutrit using the 5-observable Klyachko, Can, Binicio?glu, and Shumovsky inequality, which is arguably the most fundamental noncontextuality inequality for testing quantum mechanics (QM). We quantify the effect of systematics in our experiment by purposely scanning the degree of signaling between measurements, which allows us to place realistic bounds on the nonclassicality of the observed correlations. Our results violate the classical bound for this experiment by up to 25 standard deviations, while being in agreement with the QM limit. In order to test the prediction of QM that the contextual fraction increases with the number of observables, we gradually increase the complexity of our measurements from 5 up to 121 observables. We ?nd stronger-than-classical correlations in all prepared scenarios up to 101 observables, beyond which experimental imperfections blur the quantum-classical divide.
关键词： quantum contextuality,noncontextuality inequality,contextual fraction,quantum mechanics,trapped ion
更新于2025-09-10 09:29:36
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Dependable Visual Light-Based Indoor Localization with Automatic Anomaly Detection for Location-Based Service of Mobile Cyber-Physical Systems
摘要： Indoor localization has become popular in recent years due to the increasing need of location-based services in mobile cyber-physical systems (CPS). The massive deployment of light emitting diodes (LEDs) further promotes the indoor localization using visual light. As a key enabling technique for mobile CPS, accurate indoor localization based on visual light communication remains nontrivial due to various non-idealities such as attenuation induced by unexpected obstacles. The anomalies of localization can potentially reduce the dependability of location-based services. In this article, we develop a novel indoor localization framework based on relative received signal strength. Most importantly, an efficient method is derived from the triangle inequality to automatically detect the abnormal LED lamps that are blocked by obstacles. These LED lamps are then ignored by our localization algorithm so that they do not bias the localization results, which improves the dependability of our localization framework. As demonstrated by the simulation results, the proposed techniques can achieve superior accuracy over the conventional approaches, especially when there exist abnormal LED lamps.
关键词： relative received signal strength,dependability,Visual light based indoor localization,mobile cyber-physical systems,triangle inequality
更新于2025-09-10 09:29:36