Projective Measurements Research Articles

Classification of data with a qudit, a geometric approach

We propose a model for data classification using isolated quantum d\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\varvec{d}$$\\end{document}-level systems or else qudits. The procedure consists of an encoding phase where classical data are mapped on the surface of the qudit’s Bloch hyper-sphere via rotation encoding, followed by a rotation of the sphere and a projective measurement. The rotation is adjustable in order to control the operator to be measured, while additional weights are introduced in the encoding phase adjusting the mapping on the Bloch’s hyper-surface. During the training phase, a cost function based on the average expectation value of the observable is minimized using gradient descent thereby adjusting the weights. Using examples and performing a numerical estimation of lossless memory dimension, we demonstrate that this geometrically inspired qudit model for classification is able to solve nonlinear classification problems using a small number of parameters only and without requiring entangling operations.

Fisher information rates in sequentially measured quantum systems

We consider the impact that temporal correlations in the measurement statistics can have on the achievable precision in a sequential metrological protocol. In this setting, and for a single quantum probe, we establish that it is the transitions between the measurement basis states that plays the most significant role in determining the precision, with the resulting conditional Fisher information being interpretable as a rate of information acquisition. Projective measurements are shown to elegantly demonstrate this in two disparate estimation settings. Firstly, in determining the temperature of an environment and, secondly, to ascertain a parameter of the system Hamiltonian. In both settings we show that the sequential estimation approach can provide a useful method to enhance the achievable precision.

Enhance the coherence of open two-level system through the superposition of environments

Dynamics of a two-level system in the superposition of two dephasing environments with Ohmic-like spectral density is studied when considering initial system-environment correlations. The quantum system and one environment are treated as whole thermal equilibrium state, while the other environment is at thermal equilibrium state alone. Which environment the system interacts with is determined by an ancillary two-level system. When the system interacts with mixture of two sub-Ohmic environments, initial correlations can make the mixed dynamics non-Markovian. For two identical sub-Ohmic environments, if performing the projective measurement on the ancillary two-level system at the special time points, whatever the initial state of the system is, the coherence can be enhanced. For two different environments with βħω0/2>>, we get the approximate expression about the coherence of the system when measuring the ancillary two-level system.

Fuzzy-based performance measurement of building construction projects: a case study

Fuzzy-based performance measurement of building construction projects: a case study

STRUCTURAL EQUATION MODEL-BASED PERFORMANCE MEASUREMENT SYSTEM FOR TRANSFERRING PPP WATER PROJECTS: A CHINA PERSPECTIVE

A series of performance measurement need to be carried out throughout the project life cycle to ensure the successful transfer of public-private partnership (PPP) assets and meet stakeholder needs. More and more water projects are stepping into the transfer phase, but less studies carry out in-depth and systematic discussion on the performance measurement of PPP water projects at the transfer phase. Hence, to fill this gap, this research establishes a new performance measurement system (PMS) for evaluating the performance of the PPP projects stepping into the transfer phase based on the key performance indicators (KPIs). Through case study, expert interview and questionnaire, this paper formulates the logical basis behind PPP water projects at the transfer phase and subsequently constructs the transfer performance measurement system (TPMS) of these projects. Then, it conducts a confirmatory analysis of the impact relationship between the indicators based on structural equation modeling (SEM). Findings of expert interview and questionnaire indicate that there are 7 primary and 26 secondary indicators, and the model has a good fit. The TPMS will provide governments, operators and other stakeholders with a comprehensive and complete understanding as to indicators required of an effective performance measurement of PPP water projects.

Projection-based TOPSIS method to MAGDM in dual probabilistic linguistic information environment

The dual probabilistic linguistic term sets (DPLTSs) are more effective than PLTSs in solving the problem of multi-attribute group decision-making (MAGDM). In this paper, an improved TOPSIS method is developed combining the TOPSIS method and projection measure of DPLTS to supplement the existing research. Firstly, considering the mathematical characteristics of DPLTS, this paper defines the concepts of the module, cosine function, and projection of DPLTS, and then proves the mathematical properties of the cosine function. Secondly, considering the uncertainty of decision-making problems, the weight-solving models are established respectively under the condition that the weight information is completely unknown and partially known. Furthermore, a novel DPLPrj-TOPSIS approach is established based on the projection measure proposed. It involves integrating experts’ DPLTS evaluations, normalizing different DPLTSs, calculating alternatives’ relative closeness and score, etc. Secondly, the proposed method’s feasibility is demonstrated through a case study that entails selecting network promotion plans for food manufacturers. Finally, the proposed method’s effectiveness and validity are verified by comparing and analyzing it with the traditional TOPSIS method based on a distance measure and other existing decision methods.

Compatibility of projective measurements subject to white noise and loss

Compatibility of projective measurements subject to white noise and loss

Sharing Bell nonlocality of bipartite high-dimensional pure states using only projective measurements

Sharing Bell nonlocality of bipartite high-dimensional pure states using only projective measurements

Stability of a quantum skyrmion: Projective measurements and the quantum Zeno effect

Stability of a quantum skyrmion: Projective measurements and the quantum Zeno effect

Improving Long-Term Projection in Nipple Reconstruction Using a New Human-Derived Acellular Dermal Matrix

Background: Loss of projection is a very common complaint after nipple reconstruction. In this paper, we present our experience with the use of a novel human cadaver-donor-derived acellular dermal matrix, named MODA (Matrice Omologa Dermica Acellulata) from the Regional Skin Bank to improve and stabilize nipple projection after oncoplastic breast surgery. Methods: We did a retrospective analysis of patients undergoing nipple reconstruction with local flap and MODA graft after breast reconstruction between February 2019 and May 2021. The analysis was done following the Declaration of Helsinki and was approved by the ethics committee; written consent was sought from all the participants. The main evaluation criterion was nipple projection measurement, performed immediately after surgery, 6 and 12 months postoperatively. The secondary endpoints were complications and patients’ satisfaction. Results: In this study, 50 patients underwent nipple reconstruction, with 57 reconstructed nipples. All cases except six followed delayed breast reconstruction. The patients were divided into 3 groups, according to the breast reconstructive technique. There were three cases of delayed wound healing and two cases of partial necrosis, but all of the cases healed by secondary intention. Five percent of the patients (3/57 reconstructions) presented more than 60% of nipple projection loss and required another procedure. The other reconstructed nipples maintained an average of over 60% projection after 12 months. Conclusion: The described technique presents a high success rate associated with low complications. Indeed, it provides the advantages of nipple reconstruction with ADM with low costs, appears safe after radiotherapy, and has similar results when used after different reconstructive techniques.

Unified light-matter Floquet theory and its application to quantum communication

Periodically driven quantum systems can exhibit a plethora of intriguing nonequilibrium phenomena that can be analyzed using Floquet theory. Naturally, Floquet theory is employed to describe the dynamics of atoms interacting with intense laser fields. However, this semiclassical analysis cannot account for quantum-optical phenomena that rely on the quantized nature of light. In this paper, we take a significant step to go beyond the semiclassical description of atom-photon coupled systems by unifying Floquet theory with quantum optics using the framework of full-counting statistics. This is achieved by introducing counting fields that keep track of the photonic dynamics. This formalism, which we dub “photon-resolved Floquet theory” (PRFT), is based on two-point tomographic measurements, instead of the two-point projective measurements used in standard full-counting statistics. Strikingly, the PRFT predicts the generation of macroscopic light-matter entanglement when atoms interact with multimode electromagnetic fields, thereby leading to complete decoherence of the atomic subsystem in the basis of the Floquet states. This decoherence occurs rapidly in the optical-frequency regime, but is negligible in the radio-frequency regime. Our results thus pave the way for the design of efficient quantum memories and quantum operations. Finally, employing the PRFT, we propose a quantum-communication protocol that can significantly outperform the state-of-art few-photon protocols by two orders of magnitude or better. The PRFT potentially leads to insights in various Floquet settings including spectroscopy, thermodynamics, quantum metrology, and quantum simulations. Published by the American Physical Society 2024

Sex estimation based on mandibular measurements.

Medical imaging and machine learning are beneficial approaches in physical and forensic anthropology. They are particularly useful for the development of models for sex identification based on bone remains. The present study uses machine learning algorithms to create models for sex estimation based on mandibular measurements. The sample included head CT scans of 239 adult Bulgarians (116 males and 123 females). Three-dimensional coordinates of 45 landmarks of the mandible were acquired from segmented polygonal models of the skulls of these individuals. Two datasets of mandibular measurements were assembled. The first dataset included 51 measurements: linear, projective, and angular measurements. The second dataset included 990 interlandmark distances. Seven machine learning algorithms (Support Vector Machines, Neural Network, Naïve Bayes, Random Forest, J48, JRip, and Logistic Regression) were applied to the two datasets, and the classification accuracy was evaluated by 10x5-cross-validation. The selection of the best subsets of attributes specific to each of the abovementioned algorithms was done based on the attribute importance evaluated by an attribute selection scheme. In general, the sub-symbolic algorithms achieved higher results than the symbolic ones, except for the logistic regression. The best classification model was learnt by the Support Vector Machines algorithm, which achieved an accuracy of 95.3% on a dataset described by 19 interlandmark distances. In both datasets, the application of advanced attribute selection has led to an increase in the classification accuracy of all algorithms used in the experiments.

Entanglement Transitions in Unitary Circuit Games

Repeated projective measurements in unitary circuits can lead to an entanglement phase transition as the measurement rate is tuned. In this work, we consider a different setting in which the projective measurements are replaced by dynamically chosen unitary gates that minimize the entanglement. This can be seen as a one-dimensional unitary circuit game in which two players get to place unitary gates on randomly assigned bonds at different rates: the “entangler” applies a random local unitary gate with the aim of generating extensive (volume-law) entanglement. The “disentangler,” based on limited knowledge about the state, chooses a unitary gate to reduce the entanglement entropy on the assigned bond with the goal of limiting to only finite (area-law) entanglement. In order to elucidate the resulting entanglement dynamics, we consider three different scenarios: (i) a classical discrete height model, (ii) a Clifford circuit, and (iii) a general U(4) unitary circuit. We find that both the classical and Clifford circuit models exhibit phase transitions as a function of the rate that the disentangler places a gate, which have similar properties that can be understood through a connection to the stochastic Fredkin chain. In contrast, the entangler always wins when using Haar random unitary gates and we observe extensive, volume-law entanglement for all nonzero rates of entangling. Published by the American Physical Society 2024

Optimization of parameters for a fringe projection measurement system by use of an improved differential evolution method.

Fringe projection 3D measurement is widely used for object surface reconstruction. While improving measurement accuracy is a crucial task. Measurement accuracy is profoundly affected by various optical structural parameters. However, the current practice of system construction lacks theoretical guidelines and often relies on the experience of the operator, inevitably leading to unpredictable error. This paper investigates a theoretical optimization model and proposes an automatic optimization method for qualitatively determining the multiple optimal optical structural parameters in fringe projection measurement system. The aim is to enhance measurement accuracy conducting a rational comprehensive optimal structural parameters design prior to the system construction. Firstly, the mathematical model of the measurement system is established based on the principle of optical triangulation, and the phase sensitivity criterion is defined as the optimization norm. Within the full measurement range, the optimization merit function is formulated by combing three positions: the center position, the left and right boundary of the CCD. The imaging effectiveness criteria and sensor geometric dimensions are taken into account as the constraint boundaries. Subsequently, a combined improved differential evolution and Levy flight optimization algorithm is applied to search for the optimal parameters. The optimal structural parameters of the system were designed based on the optimization process. Experimental results validated the improvement in measurement accuracy achieved by the optimized structural parameters.

Quantum state transfer through system-environment correlation

Quantum state transfer protocol based on system-environment correlation is studied. Different from that in protocol of quantum teleportation, in the present transfer protocol, parties do not share entangled state initially. The state factors are transmitted among parties through their common memory-environment. Explicitly, with the generation of system-environment correlation, state factors parameterized on the probe system can be transmitted to the environment by performing proper projective measurement on the probe system. Then after knowing the results of former measurements, other parties can estimate the state factors by preparing proper detectors that evolve with the memory environment for a proper period of time. In this regard, quantum state is transmitted among different parties through system-environment correlation. Since quantum decoherence appears along with the generation of system-environment correlation, using the present transfer protocol, one can transmit quantum state even after the characteristic time of quantum decoherence.

Fast quantum interference of a nanoparticle via optical potential control

We introduce and theoretically analyze a scheme to prepare and detect non-Gaussian quantum states of an optically levitated particle via the interaction with light pulses that generate cubic and inverted potentials. We show that this approach allows to operate on sufficiently short time- and length scales to beat decoherence in a regime accessible in state-of-the-art experiments. Specifically, we predict the observation of single-particle interference of a nanoparticle with a mass above 108 atomic mass units delocalized by several nanometers, on timescales of milliseconds. The proposed experiment uses only optical and electrostatic control, and can be performed at about 10-10 mbar and at room temperature. We discuss the prospect of this method for coherently splitting the wavepacket of massive dielectric objects without using either projective measurements or an internal level structure.

A method based on q-rung orthopair fuzzy cognitive map and TOPSIS method for failure mode and effect analysis considering risk causal relationships

As a preventive maintenance technique, failure mode and effect analysis (FMEA) is widely applied to determine and eradicate possible failures. In recent years, many FMEA methods have been developed to address the limitations of traditional FMEA methods in failure mode (FM) assessment, weight calculation, and FM prioritization in complex uncertain environments. However, due to the complexity of equipment, systems, services, etc., there is an inevitable influence on causal relationships between FMs, which is rarely considered by existing methods. Therefore, a novel FMEA method, which integrates the technique for order preference by similarity to the ideal solution (TOPSIS) of q-rung orthopair fuzzy set (q-ROFS) and q-rung orthopair fuzzy cognitive map (q-ROFCM), is proposed for reasoning the relationships between FMs. The design of the novel method, named q-ROFCM FMEA, involves three stages. The q-ROFS is applied to evaluate the risk factors for capturing more ambiguous information in the first stage. The q-ROFCM is proposed and the causal relationship between FMs is integrated to describe the impact of the relationships on the evaluation results through the dynamic behavior of FMs in the second stage. In the third stage, the TOPSIS method is applied to determine the priority ranking of FMs based on more reliable similarity measurement results of the projection measure. The proposed new method is applied to the FM risk assessment of power units in the railway turnout system. The competitiveness and effectiveness of the proposed method have been demonstrated by comparison with other classic methods and sensitivity analysis.

On the trivializability of rank-one cocycles with an invariant field of projective measures

On the trivializability of rank-one cocycles with an invariant field of projective measures

Anti-corruption measures in large-scale construction projects

Abstract Accepted by: Konstantinos Nikolopoulos Corruption is affecting many developing countries, manifested often in construction projects. This study identifies the factors causing corruption and prioritizes anti-corruption measures in large-scale urban construction projects with empirical data from a developing country: Iran. The model consists of six main dimensions including 24 measures and was developed by systematically reviewing the literature as well as collecting primary data through interviewing experts. The model prioritizes the anti-corruption measures through an integrated method of the fuzzy best-worst method and fuzzy measurement alternatives and ranking according to the compromise solution. The field of corruption has a multi-faceted nature and inherent uncertainty, which necessitates this integrated approach for its analysis. The results reveal that the ‘lawlessness and deregulation in public construction projects’ and ‘top management and leader commitment’ are the most important causes of corruption. This study offers two main contributions. First, it develops a conceptual model to evaluate and prioritize anti-corruption measures; second, it generates practical solution for reducing corruption in municipal and urban management, thus enhancing the prospects of successful construction projects in developing countries.

Mentor initialed multiparty hierarchical joint remote preparation of an arbitrary n-qudit state via generalized Bell states

We propose a protocol to Mentor initiated hierarchical joint remote prepare the arbitrary n-qudit state with generalized Bell states.The agents share generalized Bell states with the Mentor. The Mentor performs five-qudit projective measurements on his entangled particles to initiate the quantum channel shared by the agents. All the senders share the information of the prepared state and make quantum measurements on their particles based on the state to be prepared. The agent in the upper grade needs only the assistance of one of the agents in the lower grade to reconstruct the original state, while the agents in the lower grade need the assistance of all the other agents to recover the original state. It is more convenient in application than others since the agents in the protocol only requires two-particle entanglement for Mentor initiated hierarchical joint remote preparation of an arbitrary n-qudit state.