7,176 research outputs found
How to estimate the differential acceleration in a two-species atom interferometer to test the equivalence principle
We propose a scheme for testing the weak equivalence principle (Universality
of Free Fall) using an atom-interferometric measurement of the local
differential acceleration between two atomic species with a large mass ratio as
test masses. A apparatus in free fall can be used to track atomic free-fall
trajectories over large distances. We show how the differential acceleration
can be extracted from the interferometric signal using Bayesian statistical
estimation, even in the case of a large mass and laser wavelength difference.
We show that this statistical estimation method does not suffer from
acceleration noise of the platform and does not require repeatable experimental
conditions. We specialize our discussion to a dual potassium/rubidium
interferometer and extend our protocol with other atomic mixtures. Finally, we
discuss the performances of the UFF test developed for the free-fall (0-g)
airplane in the ICE project (\verb"http://www.ice-space.fr"
Going micro: Analysing SAM multipliers for the dairy chain on Reunion Island
This poster presents a study on the multiplier effects in the dairy chain on Reunion Island. This Indian Ocean island is one of the French overseas departments. However, it struggles with similar problems as the developing areas in its neighbourhood, high levels of unemployment especially being a major concern. The agricultural sector justifies the state support it receives by stressing its role in the creation of employment and economic activity. Our focus is on the dairy sector of the Island, which is relatively recent and highly organized. Local milk production has increased over the years and our aim is to calculate the economywide impact of this trend. We use a social accounting matrix with disaggregated accounts for the dairy sector to calculate the impact of changes in this sector.Dairy, SAM, La Reunion, Livestock Production/Industries,
I.C.E.: An Ultra-Cold Atom Source for Long-Baseline Interferometric Inertial Sensors in Reduced Gravity
The accuracy and precision of current atom-interferometric inertialsensors
rival state-of-the-art conventional devices using artifact-based test masses .
Atomic sensors are well suited for fundamental measurements of gravito-inertial
fields. The sensitivity required to test gravitational theories can be achieved
by extending the baseline of the interferometer. The I.C.E.
(Interf\'erom\'etrie Coh\'erente pour l'Espace) interferometer aims to achieve
long interrogation times in compact apparatus via reduced gravity. We have
tested a cold-atom source during airplane parabolic flights. We show that this
environment is compatible with free-fall interferometric measurements using up
to 4 second interrogation time. We present the next-generation apparatus using
degenerate gases for low release-velocity atomic sources in space-borne
experiments
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