Quantum Metrology And Fundamental Physical Constants

The object of this NATO Advanced Study Institute was to pre sent a tutorial 'introduction both to the basic physics of recent spectacular advances achieved in the field of metrology and to the determination of fundamental physical constants. When humans began to qualify their description of natural phenomena, metrology, the science of measurement, developed along side geometry and mathematics. However, flam antiquity to modern times, the role of metrology was mostly restricted to the need of commercial, social or scientific transactions of local or at most national scope. Beginning with the Renaissance, and particularly in western Europe during the last century, metrology rapidly developed an international character as a result of growing needs for more accurate measurements and common standards in the emerging indus trial society. Although the concerns of metrology are deeply rooted to fundamental sciences, it was, until recently, perceived by much of the scientific community as mostly custodial in character.

One of the exciting characteristics of metrology is its intimate relationship between fundamental physics and the leading edge of technology which is needed to perform advanced and challenging experiments and measurements. This title includes a set of lectures which present the relevant progress in Metrology.

This book discusses the theory of quantum effects used in metrology, and presents the author’s research findings in the field of quantum electronics. It also describes the quantum measurement standards used in various branches of metrology, such as those relating to electrical quantities, mass, length, time and frequency. The first comprehensive survey of quantum metrology problems, it introduces a new approach to metrology, placing a greater emphasis on its connection with physics, which is of importance for developing new technologies, nanotechnology in particular. Presenting practical applications of the effects used in quantum metrology for the construction of quantum standards and sensitive electronic components, the book is useful for a broad range of physicists and metrologists. It also promotes a better understanding and approval of the new system in both industry and academia. This second edition includes two new chapters focusing on the revised SI system and satellite positioning systems. Practical realization (mise en pratique) the base units (metre, kilogram, second, ampere, kelvin, candela, and mole), new defined in the revised SI, is presented in details. Another new chapter describes satellite positioning systems and their possible applications. In satellite positioning systems, like GPS, GLONASS, BeiDou and Galileo, quantum devices – atomic clocks – serve wide population of users.

The reliability and accuracy of systems of measurement continue to advance. We are about to enter a period of the most stable measurement system we can imagine with the anticipated new definitions of the SI units of measurement; a direct link between fundamental physics and metrology which will eliminate the current definition of the kilogram, until now based upon an artifact. This book presents selected papers from Course 185 of the Enrico Fermi International School of Physics, held in Varenna, Italy, in July 2012 and jointly organized with the Bureau International des Poids et Mesures (BIPM). The papers delivered at the school covered some of the most advanced topics in the discipline of metrology, including nano-technologies; quantum information and quantum devices; biology and medicine; food; surface quality; ionising radiation for health, environment, art and archaeology; and climate. The continuous and striking advances in basic research concerning atomic frequency standards operating both in the visible range and at microwave levels and the applications to satellite systems are also considered, in the framework of a historical review of the international organization of metrology, as are the problems inherent in uncertainty statements and definitions. This book will be of interest to all those whose work involves scientific measurement at the highest levels of accuracy.

The International System of Units, the SI, provides the foundation for all measurements in science, engineering, economics, and society. The SI has been fundamentally revised in 2019. The new SI is a universal and highly stable unit system based on invariable constants of nature. Its implementation rests on quantum metrology and quantum standards, which base measurements on the manipulation and counting of single quantum objects, such as electrons, photons, ions, and flux quanta. This book explains and illustrates the new SI, its impact on measurements, and the quantum metrology and quantum technology behind it. The book is based on the book ?Quantum Metrology: Foundation of Units and Measurements? by the same authors. From the contents: -Measurement -The SI (Système International d?Unités) -Realization of the SI Second: Thermal Beam Cs Clock, Laser Cooling, and the Cs Fountain Clock -Flux Quanta, Josephson Effect, and the SI Volt -Quantum Hall Effect, the SI Ohm, and the SI Farad -Single-Charge Transfer Devices and the SI Ampere -The SI Kilogram, the Mole, and the Planck constant -The SI Kelvin and the Boltzmann Constant -Beyond the present SI: Optical Clocks and Quantum Radiometry -Outlook

The International System of Units (SI) is the world's most widely used system of measurement, used every day in commerce and science, and is the modern form of the metric system. It currently comprises the meter (m), the kilogram (kg), the second (s), the ampere (A), the kelvin (K), the candela (cd) and the mole (mol)). The system is changing though, units and unit definitions are modified through international agreements as the technology of measurement progresses, and as the precision of measurements improves. The SI is now being redefined based on constants of nature and their realization by quantum standards. Therefore, the underlying physics and technologies will receive increasing interest, and not only in the metrology community but in all fields of science. This book introduces and explains the applications of modern physics concepts to metrology, the science and the applications of measurements. A special focus is made on the use of quantum standards for the realization of the forthcoming new SI (the international system of units). The basic physical phenomena are introduced on a level which provides comprehensive information for the experienced reader but also provides a guide for a more intense study of these phenomena for students.

Proceedings of the NATO Advanced Study Institute, Erice, Italy, May 2-12, 1987

The exchange between physics and metrology is always fascinating and exciting. Many are the open problems in physics that call for extremely precise standards, many are the advances in metrology made possible by a deep and assiduous study of the underlying physics. One has just to think of the enormous sophistication required in the measurements of some absolute quantities such as the Avogadro, the gas, or the gravitational constants. It is also worth noticing that not only the units of a metrological system are interrelated through the fundamental constants, but also the latter find their full significance when they are determined through the most exacting metrological experiments. Over the past decade many improvements took place and these are discussed in this book; from one side the old caesium SI second definition has found a new realisation, with the “fountain” approach, replacing the classical thermal atomic beam. The use of “cold” atom techniques, in which bunches of inert atoms are collected, slowed down, and cooled, has opened a number of new and unexpected avenues for metrology and fundamental constants; one of these possibilities being the atom interferometry. Another important “quantum jump” was the demonstration of the possibility of performing a direct frequency division in the visible, using ultra short femtosecond pulses. In addition, the possibility of “counting” electrons or photons gave a fundamental support to the development of single-electron capacitance standards and to new scenarios in the absolute calibration of photo-detectors.