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.