International School Quantum Metrology and Fundamental Constants

LNE and METAS organise an international school on "Quantum Metrology and Fundamental Constants" at the Centre de Physique des Houches - France from 1 to 12 October 2007.

The aim of this school is to strengthen the links between the scientific and metrological communities, promoting the metrological approach to the first community and in reverse offering to the second a sight of scientific and technological advances enabling eventual metrological applications. Such a meeting between these two communities turns out to be opportune within the present context of the general discussion on the possible redefinition of the international system of units (SI) based on fundamental constants. This revolution of the SI, which includes redefinitions of the kilogramme, ampere, kelvin and mole, could occur in 2011. The discussion implying metrologists, physicists and chemists raises questions about experimental inconsistencies and on the general structure of the SI (definitions of units, values of fundamental constants, "mises en pratique" of definitions …).

The proposed school consists not only of a series of lectures but also of round tables and a final debate, two poster sessions and a demonstration session to put the use of a specific mathematical tool in practice. The school will not cover the whole field of fundamental metrology but will be limited to the quantum field, i.e. the study and the operating of quantum phenomena in the framework of the realisation and the reproduction of SI units in different fields (electricity&magnetism, time&frequency, mass, temperature, …).

Major subjects will be tackled, such as: "The SI today and tomorrow", the fundamental constants and their determinations (fine structure constant, Planck constant, Rydberg constant, Boltzmann constant …) through different sets of experiences (watt balances, measurement of h/m ratios, metrological triangles …), the adjustment of their values by the CODATA group, the present maintenance of fundamental units (atomic funtains, optical clocks, electrical quantum standards, thermometers based on Coulomb blockade and on shot noise, …). General lectures which are not given in the other schools on metrology are proposed. They will deal with the main manufacturing technics in micro and nanotechnology, the general methods for ultra low noise measurements, the use of mathematical tools used for data analysis (Allan variances) or for uncertainty evaluation (recent methods involving distribution propagation by means of Monte Carlo simulation). Finally, other subjects concerning metrologists as well as physicists will be about very specific measurement technics used in several domains (thermometry, Electricity, Spectrometry ..) and implying quantum devices (for example, SQUID).

The program includes 31 lectures and two poster sessions which will be preceded by a session of one hour during which students will present their own poster in a single slide. Some students will be asked to organise and to lead round tables on specific questions. These discussions will be held during the spare time. A debate will close the school by going back to the key questions presented at the beginning of these two weeks.

Final Report 2007-11-09

The school gathered 83 participants (48 students, 32 lecturers and 3 organisers) from 20 countries. One third of the participants came from the academic area, the two other thirds came from NMIs. The program included 33 lectures (50 min) and two poster sessions (about 4 hours each, 43 posters) during which the students presented their work. A debate closed the school by going back to the key questions presented at the beginning of the school.

The aim of the school program was to present the implications of quantum mechanics in the field of metrology and to give an outlook on possible developments. The lectures successfully reviewed the SI, fundamental physical constants, quantum standards and quantum metrology techniques, by covering both theoretical and experimental aspects. Major subjects were tackled, such as the present and future SI, the constants of Nature and their determinations (a, R¥, h, NA, kB …) through different sets of experiences (measurement of g-2, h/m ratios, watt balances, X-ray crystal density measurements of Si spheres, quantum metrological triangles, test of the Einstein relation …), and the adjustment of the values of the fundamental constants by the CODATA group. Great progress and very recent results have been reported both on the determination of constants and on the maintenance of fundamental units (atomic fountains, optical clocks, electrical quantum standards, thermometers based on Coulomb Blockade and on shot noise, ...). Universality tests have been discussed. There were general lectures which have not yet been given a the other schools on metrology. They dealt with the main manufacturing techniques in micro and nanotechnology, the general methods for ultra low noise measurements, the use of mathematical tools in data analysis (Allan Variances) or for uncertainty evaluation (recent method involving distribution propagation by means of Monte Carlo simulation) and specific measurement techniques used in several domains (thermometry, electricity, spectrometry …) and implying quantum devices such as SQUIDs.
The school has resulted in a very fruitful meeting of two communities (atomic and solid state physics), which usually don’t come together. As expected, the different (« opposite ») sensibilities and points of view have been expressed during these two weeks, mainly focused on the confidence questions about quantum phenomena, their exactness, and on the key issues about the future reform of the International System of units (SI) with the ultimate goal of defining all units in terms of fundamental constants.
Proceedings of peer-reviewed lectures will be published in 2008 in the series of European Journal of Physics - Special Topics, edited by EDP Science and Springer.

Electricity and Magnetism (EM)
Coordinating Institute
LNE (France)
Participating Partners
METAS (Switzerland)