Argument for a direct realization of the quantum metrological triangle

The quantum metrological triangle experiment, which is under development at the Bureau National de Metrologie-Laboratoire Central des industries Elect riques (BNM-LCIE), consists of applying Ohm's law directly to the quantitie s related to the single-electron tunnelling (SET) effect, the ac Josephson effect (JE) and the quantum Hall effect (QHE). The goal of this experiment is to test, at a significant level of uncertainty of about 1 part in 10(8), the coherence of the constants involved in these three quantum phenomena: the Josephson constant K-J, expected to correspond to the ratio 2e/h (where e is the elementary charge and h the Planck constant); the von Klitzing co nstant R-K, in relation to the quantum resistance h/e(2); and a new constan t Q(x), defined here as the estimate of e. Moreover, realization of the met rological triangle experiment, combined with the experiment being developed at the NIST aimed at charging a capacitor by means of a SET pump, will giv e information liable to be taken into account in future adjustments of the fundamental constants without requiring any hypothesis regarding the physic al phenomena involved. The combination of these two experiments should yiel d a new value of R-K in ohms of the International System of Units (SI). The broad outlines of our experimental set-up are given, along with the expect ed uncertainties in both the short and long terms.