Field Of Metrology Research Articles

Exponential Clustering of Bipartite Quantum Entanglement at Arbitrary Temperatures

Macroscopic quantum effects play central roles in the appearance of inexplicable phenomena in low-temperature quantum many-body physics. Such macroscopic quantumness is often evaluated using long-range entanglement, i.e., entanglement in the macroscopic length scale. The long-range entanglement not only characterizes the novel quantum phases but also serves as a critical resource for quantum computation. Thus, the problem that arises is under which conditions can the long-range entanglement be stable even at room temperatures. Here, we show that bi-partite long-range entanglement is unstable at arbitrary temperatures and exponentially decays with distance. Our theorem provides a no-go theorem on the existence of the long-range entanglement. The obtained results are consistent with the existing observations that long-range entanglement at non-zero temperatures can exist in topologically ordered phases, where tripartite correlations are dominant. In the derivation of our result, we introduce a quantum correlation defined by the convex roof of the standard correlation function. We establish an exponential clustering theorem for generic quantum many-body systems for such a quantum correlation at arbitrary temperatures, which yields our main result by relating quantum correlation to quantum entanglement. As a simple application of our analytical techniques, we derived a general limit on the Wigner-Yanase-Dyson skew information and the quantum Fisher information, which will attract significant attention in the field of quantum metrology. Our work reveals novel general aspects of low-temperature quantum physics and sheds light on the characterization of long-range entanglement.

Improving the dimensional accuracy of 3D x-ray microscopy data

X-ray microscopy instruments have the unique ability to achieve nondestructive imaging with higher spatial resolutions than traditional x-ray computed tomography (CT) systems. This unique ability is of interest to industrial quality control entities, as they deal with small features in precision manufactured parts (with tolerances in the order of ±25 µm or better). Since many of today’s technology and manufacturing companies demand increasingly higher levels of precision, accuracy, and reliability for dimensional measurements on feature sizes that are much smaller than 5 mm, it would be ideal to further expand the imaging capabilities of x-ray microscopy to the field of precision metrology. To address such demand, this paper describes the development of a measurement workflow, through a package consisting of hardware and software, to improve the accuracy of dimensional data obtained with 3D x-ray microscopes (XRMs)—also known as sub-micrometer CT systems. The measurement workflow, called Metrology Extension (MTX), was designed to adjust and configure the XRM instrument work-zone to perform dimensional measurement tasks. The main adjustments of an XRM instrument through the MTX workflow, which must be implemented before scanning parts of interest for dimensional evaluation, include applying a distortion map correction on the image projections produced by the x-ray detector and a voxel scale correction. The main purpose of this article is to present, evaluate, and analyze the experimental results of various measurement tests to verify the metrological performance of several XRM systems operating with the MTX workflow. The main results show that these systems can produce repeatable and reproducible measurements, with repeatability standard deviations of the order of 0.1 μm and reproducibility standard deviations of less than 0.5 μm. In addition, coordinate-based 3D XRM measurements produce dimensional accuracies comparable to those offered by high-precision tactile coordinate measurement machines (with deviations within the range of ±0.95 µm). Therefore, once the MTX workflow is executed, XRM instruments can be used to measure small volumes, in the order of (5 mm)3 or less, with improved dimensional accuracy.

Advances in Microwave Large-Signal Metrology: From Vector-Receiver Load-Pull to Vector Signal Network Analyzer and Time-Domain Load-Pull Implementations (Invited Paper)

Radiofrequency (RF) power amplifiers (PAs) are important elements of modern communication systems. The most important components in PAs are the transistors, which are operated under large-signal regimes in such applications. Designing and optimizing PAs are challenging tasks that demand the highest accuracy on large-signal measurements at both device and circuit levels. Large-signal power transistor characterization demands the development and utilization of high-frequency and low-frequency load-pull systems. Furthermore, the static and dynamic characterization of two-input PAs requires the development of new measurement systems that consist of an nonlinear vector network analyzer (NVNA) and an arbitrary waveform generators (AWG). This paper reviews the research activities, achievements, and current research goals at CICESE Research Center in Mexico in the large-signal microwave metrology field.

Quantum gravimetry going toward real applications

Gravimetry techniques play significant roles in the fields of metrology, geology, and industrial-related applications such as resource exploration and navigation. Classical absolute gravimeters and absolute gravity gradiometers have long been limited by mechanical wear and lower sampling rate, which make them powerless for long-term continuous observations and applications on moving platforms. At the end of the last century, the inception of atom interferometers (AIs) brought a new technical solution. In AIs, laser pulses are employed to manipulate atom groups in a vacuum to achieve splitting, redirection, and recombination.

Structure of digital metrological twins as software for uncertainty estimation

Abstract. Ongoing digitalization in metrology and the ever-growing complexity of measurement systems have increased the effort required to create complex software for uncertainty estimation. To address this issue, a general structure for uncertainty estimation software will be presented in this work. The structure was derived from the Virtual Coordinate Measuring Machine (VCMM), which is a well-established tool for uncertainty estimation in the field of coordinate metrology. To make it easy to apply the software structure to specific projects, a supporting software library was created. The library is written in a portable and extensible way using the C++ programming language. The software structure and library proposed can be used in different domains of metrology. The library provides all the components necessary for uncertainty estimation (i.e., random number generators and GUM S1-compliant routines). Only the project-specific parts of the software must be developed by potential users. To verify the usability of the software structure and the library, a Virtual Planck-Balance, which is the digital metrological twin of a Kibble balance, is currently being developed.

Occupational standards application when building up the modern professional metrologist competences

This article develops the issues of building up the federal state educational standards, major professional academic programs for specialists in the field of metrology, taking into account occupational standards. The regulatory documents characterizing the metrology specialists activities have been analyzed. A structure to build up an occupational standards system in the field of metrology has been put forward.

Recent Progress in Radon Metrology at IFIN-HH, Romania

The practical implementation of the European Council Directive no. 2013/59/EURATOM in Romania requires reliable indoor measurements of the radon (222Rn) activity concentration in air. In Romania, several Testing Laboratories were designated for radon activity and/or radon activity concentration in air measurements by the Romanian National Commission for Nuclear Activities Control (CNCAN). The calibration of the instruments used for indoor radon activity concentration measurements is very important. IFIN-HH, through its Ionizing Radiation Metrology Laboratory (LMRI), performed advanced research in the field of radon metrology, using radon standard sources prepared by LMRI, its radon chamber facility and a new reference radon monitor. The most recent results are described in this article. The radon chamber facility from IFIN-HH was technically improved, and new equipment and methods were set up and tested in order to provide new calibration services for customers. Additionally, calibration of the radon monitors was performed, as well as of the systems with solid-state nuclear track detectors, used for radon in air activity concentration measurements. IFIN-HH/LMRI obtained the CNCAN designation as Calibration Laboratory for installations measuring the radon activity concentration in air.

News from the BIPM laboratories—2021

In order to fulfil its mission to ensure and promote the global comparability of measurements, the BIPM operates laboratories in the fields of physical metrology, time, ionizing radiation and chemistry. These laboratories act as centres for scientific and technical collaboration between Member States providing capabilities for international measurement comparisons on a shared cost basis. They coordinate international comparisons of national measurement standards agreed to be of the highest priority, and they establish and maintain appropriate reference standards for use as the basis of key international comparisons at the highest level and provide selected calibrations from them.

Jedan pristup razvoju digitalnog mernog blizanca na bazi numerički upravljane merne mašine

New trends in technological systems in terms of processing processes have also placed new demands on the measuring technique. The application of conventional metrology systems and the procedures that support them have become a limiting factor in terms of flexibility and measurement accuracy. The main problem problem is the rapid metrological identification of complex metrological tasks, such as, for example, shape and position tolerances for parts of medium and high accuracy. In addition to metrological identification, the problem is also the connection of metrological databases, which has a direct impact on the obtain results accuracy. In order to solve these problems, this paper presents an approach to modeling a digital measuring twin based on a numerically controlled measuring machine. In a broader sense, the developed model integrates machine and computer technologies and was applied in the field of metrology, that is, the examination of achieved tolerances on machine parts using CMM. The benefits are reflected in the fact that it is not necessary to construct expensive prototypes, it saves time, avoids collision and the most important thing in the world of industry, it saves money.

GROUP EXPERT EVALUATION OF QUALITY CRITERIA OF THE EDUCATIONAL PROGRAM FOR THE FIELD OF METROLOGY AND INFORMATION-MEASURING TECHNIQUE

The article's urgency of researching the importance of the applied national criteria for the quality of the educational program (CQEP) for higher education institutions (HEI) was established. The approach to group expert assessment of the weight of CQEP for the educational program (EP) in the field of metrology and information-measuring technique was studied. Members of one of the sectoral expert councils on technical specialties are involved in carrying out such assessments. To achieve this goal, the composition and requirements of the CQEP sub-criteria are analyzed, the algorithm of group expert assessment of the CQEP weight was proposed and substantiated, and the priority of the CQEP sub-criteria based on the conducted assessment was established. Conducting a quality assessment of EPs by experts and the National Agency for Quality Assurance in Higher Education according to clearly established criteria and sub-criteria helps to improve the quality of EPs of HEI. Although the HEI should pay attention to all the established criteria (sub-criteria), more attention should be paid to those identified by experts as the most important and those that significantly affect the quality of EP. It is established that such criteria include, first of all, training through research, human resources, teaching, and learning in the educational program. At the same time, the experts of technical specialties have the most doubts about the sub-criteria of the CQEP for internal quality assurance of the EP (K8), and this criterion itself is not considered important by them. At the same time, a large number of CQEP sub-criteria regarding the structure and content of the EP are also questionable, although they consider this criterion to be important. Therefore, these sub-criteria of the CQEP need special attention during the next revision of the set of CQEP to better balance the system of sub-criteria of the CQEP.

Digital holography as metrology tool at micro-nanoscale for soft matter

The appearance of the first laser approximately 12 years after the invention of holography by Gabor (1948) revolutionized the field of optical metrology. In fact, the invention of holographic interferometry enabled the exploitation of interferometry on non-mirror surfaces and full-scale objects. The holography-based measurement methods has been implemented to several industrial systems or in support of R&D with the aim of improving new products in many fields (automotive, aerospace, electronics, etc.). To date, holography has been considered an important measurement tool for non-destructive inspection (NDI), strain-stress measurement, and vibration analysis at various engineering sites. Recently, the new paradigm of Industry4.0 has seen the introduction of new technologies and methods of processing materials as well as the development of manufacturing approaches for the realization of innovative products. For example, direct printing, additive, and bottom-up manufacturing processes are expected to involve new ways of making products in future, and most innovative fabrication processes will be based on the manipulation of soft matter (e.g., starting from the liquid phase) that will be shaped at the nanoscale. The inherent characteristics of digital holography (DH) make it a powerful and accurate tool for the visualization and testing of final products, as well as for in situ and real-time monitoring and quantitative characterization of the processes involved during the fabrication cycle. This review aims to report on the most useful applications of soft matter, where the capabilities offered by DH, such as three-dimensional (3D) imaging, extended focus, 3D tracking, full-field analysis, high sensitivity, and a wide range of measurements from nanometers to centimeters, permit completely non-invasive characterizations on a full-scale. Several holographic experimental results of typical samples are reported and discussed where DH plays a primary role as a tool gauge for soft matter.

Sub-femtometer-resolution absolute spectroscopy with sweeping electro-optic combs

Optical frequency comb with evenly spaced lines over a broad bandwidth has revolutionized the fields of optical metrology and spectroscopy. Here, we propose a fast interleaved dual-comb spectroscopy with sub-femtometer-resolution and absolute frequency, in which two electro-optic frequency combs are swept. Electrically-modulated stabilized laser enables ultrahigh resolution of 0.16 fm (or 20 kHz in optical frequency) and single-shot measurement in 90 ms. Total 20 million points are recorded spanning 3.2 nm (or 400 GHz) bandwidth, corresponding to a spectral sampling rate of 2.5 × 10⁸ points/s under Nyquist-limitation. Besides, considering the trade-off between the measurement time and spectral resolution, a fast single-shot measurement is also realized in 1.6 ms with 8 fm (or 1 MHz) resolution. We demonstrate the 25-averaged result with 30.6 dB spectral measurement signal-to-noise ratio (SNR) by reducing the filter bandwidth in demodulation. The results show great prospect for precise measurement with flexibly fast refresh time, high spectral resolution, and high SNR.

Application of systems thinking to the establishment of metrological traceability chains

International agreements in the field of metrology and accreditation of calibration laboratories are the basis for establishing global metrological traceability. Important elements of metrological traceability are calibration of measurement standards and measuring instruments, assessment of measurement uncertainty. The International Laboratory Accreditation Cooperation has a specific policy regarding on traceability of measurement results and estimation of measurement uncertainty in calibration.
 The partial concept diagram around metrological traceability in accordance with the International Vocabulary of Metrology is proposed. This diagram contains a total of nine metrological concepts, which have most of the associative relations. There are associative relations between the concept of metrological traceability chain and concepts of metrological traceability, measurement standard, calibration and calibration hierarchy, and through the concept of measurement standard with the concept of measurement uncertainty.
 Systems thinking to the analysis of state of proposed terminological system around metrological traceability was applied. For construction of generalized metrological traceability chain, all the established properties of the system elements around the terminology system of metrological traceability were taken into account.
 Generalized metrological traceability chain for different levels of the calibration hierarchy was proposed. The proposed chain can be used to develop appropriate chains for specific areas of measurement. To achieve this, it is necessary to determine the specific measured value, the required measurement uncertainty for different levels of the calibration hierarchy and select the necessary measurement standards. Such schemes should be used in national metrology institutes and calibration laboratories.

The formation of metrology as government regulated activity in France

The article has discussed the historical process of development of metrological activity in France. It was revealed that the history of metrology is considered as an auxiliary historical and ethnographic discipline from a social and philosophical point of view as the evolution of scientific approaches to the definition of individual units of physical quantities and branches of metrology. However, in the scientific literature, the little attention is paid to the process of a development of a centralized institutional metrology system that is the organizational basis for ensuring the uniformity of measurements. It was shown that traditionally there are two periods of development of metrology based on the unification of weights and measures: the association under Charlemagne and the introduction of the decimal metric system during the French Revolution. Because this division has a mixed scientific and organizational basis, a new periodization of the development of French metrology from the position of state regulation was proposed. The highlighted stages include the primitive period and the first city-states, the time of the domination of the Roman Empire, the era of the coexistence of many measures, the chapters of Charlemagne, the feudal practices of the Middle Ages, the creation of royal standards under Henry II, the introduction and dissemination of the decimal metric system, the emergence of metrological institutes, laboratories, centers. At the State level the first step in organizing a centralized institutional metrology system was the creation of a testing laboratory, the second was the creation of National Metrological Bureau, national bodies for metrology, and the third was reorganization of the system and appointment of the National Testing Laboratory as the governing metrological body of France. Thus, the French metrology system has experienced many crises and upheavals in the process of its formation. However, France today is one of the most experienced and respected countries in the field of metrology, and at the international level, it was the one who laid the foundations for new metrological agreements, as well as the social, philosophical, scientific, political and geographical area of the new system of measures and weights.

A novel Nb superconducting joint with ultralow resistance fabricated by electron beam welding method for superconducting gravimeter

This paper presents a novel Nb superconducting joint with an ultralow resistance of 7.9 × 10−16 Ω, fabricated using the electron beam welding (EBW) method. After the EBW process, the two Nb filaments formed a single joint with a much larger grain size and smaller grain misorientation. More importantly, the resistance of the EBW Nb joint was nearly one magnitude lower than that of most conventional pressing joint. The ultralow resistance is essential for superconducting gravimeters, which require an extremely low drift rate. The EBW Nb joint allowed the superconducting gravimeter to have a much better performance when applied in the field of structural geology, geodesy, microgravity, and metrology. We believe that the EBW method could be one of the most promising joint fabrication methods for achieving maximum stability (less than 1 μgal yr−1).

Deep-learning-based fringe-pattern analysis with uncertainty estimation

Deep learning has gained increasing attention in the field of optical metrology and demonstrated great potential in solving a variety of optical metrology tasks, such as fringe analysis and phase unwrapping. However, deep neural networks cannot always produce a provably correct solution, and the prediction error cannot be easily detected and evaluated unless the ground-truth is available. This issue is critical for optical metrology, as the reliability and repeatability of the measurement are of major importance for high-stakes scenarios. In this paper, for the first time to our knowledge, we demonstrate that a Bayesian convolutional neural network (BNN) can be trained to not only retrieve the phase from a single fringe pattern but also produce uncertainty maps depicting the pixel-wise confidence measure of the estimated phase. Experimental results show that the proposed BNN can quantify the reliability of phase predictions under conditions of various training dataset sizes and never-before-experienced inputs. Our work allows for making better decisions in deep learning solutions, paving a new way to reliable and practical learning-based optical metrology.

Optimal Scheme for Quantum Metrology

AbstractQuantum metrology can achieve far better precision than classical metrology, and is one of the most important applications of quantum technologies in the real world. To attain the highest precision promised by quantum metrology, all steps of the schemes need to be optimized, which include the state preparation, parametrization, and measurement. Here the recent progresses on the optimization of these steps, which are essential for the identification and achievement of the ultimate precision limit in quantum metrology, are reviewed. It is hoped this provides a useful reference for the researchers in quantum metrology and related fields.

REASSESSMENT OF UNCERTAINTY EXPANSION BY LINEAR ADDITION OF LONG-TERM COMPONENTS FROM TOP-DOWN INFORMATION

ABSTRACTSince radiocarbon accelerator mass spectrometry (14C AMS) is considered a high-precision technique, reassessment of the measurement uncertainty has been a topic of interest. Scientists from analytical and metrological fields have developed the top-down and bottom-up measurement of uncertainty approaches. The 14C quoted error should approximate the uncertainty of long-term repetitions of the top-down approach in order to be realistic. The novelty of this paper is that the uncertainty of both approaches were approximated to each other. Furthermore, we apportioned the graphitization, instrumentation, and bias components in order to additively expand the quoted error. Our results are comparable to error multipliers and to long-term repeatability studies reported by other laboratories. Our laboratory was established in late 2012 with N2 as stripper gas and 7 years later, we changed to helium stripper. Thus, we were able to compare both gases, and demonstrate that helium is a better stripper gas. In absolute F14C units, the ranges of graphitization+bias combined uncertainties were (0.7 to 4.1) × 10–3 for N2 and (0.7–3.0) × 10–3 for He depending on the standard 14C content. The error multiplier for He defined as the expanded uncertainty over quoted error, in average, was 1.7; while without the bias, the multiplier was 1.3.

Shift-rotation absolute measurement method for irregular aperture optical surfaces based on deep learning

Absolute measurement technology has received considerable attention in the field of optical metrology owing to its high accuracy. However, to ensure accuracy of measurement, the traditional method requires the use of expensive high-precision stages and considerable time for the precise adjustment of the measured surface. A shift-rotation absolute measurement method for irregular aperture optical surfaces based on deep learning is presented here. In this method, the measured surface needs to be tested in the original position and two randomly changed positions. Furthermore, a simple and effective shift-rotation prediction convolutional neural network that can learn the mapping relationships between the binarized images of the changed position and shift-rotation is designed. The shape of the measured surface with an irregularly shaped aperture is obtained by fitting orthogonalized Zernike polynomials. Compared with the current absolute measurement method for irregular apertures, this method is highly efficient and cost-effective for adjusting the measured surface. The simulation and experimental results demonstrate the accuracy and validity of this approach.

HIGH-RESOLUTION SURFACE TEXTURE MEASUREMENTS USING A COLLABORATIVE PICK-AND-PLACE ROBOT

The ongoing trend of robotics, automation, quality control and its combination are leading to new possibilities in the field of metrology. The improvements, especially in the handling and accuracy of collaborative robotics, are enabling new applications for automated high-resolution optical 3D measurements. This is the basis for the implementation of a pick-and-place solution for automatic surface texture measurements by replacing a high precision x-y stage with a collaborative robot. In this paper two different Focus-Variation setups are compared to evaluate the uncertainty using a certified standard and a real sample.