Edouard RICHARD will defend his thesis  on the subject :

“Study and realization of a new spatio-temporal reference system based on inter-satellite links in a GNSS constellation”

The defense will take place on westeday  Wednesday, 27 of January 2016 at 14:30 in l’amphithéâtre de l’IAP (Observatoire de Paris).(Paris)

This thesis performed under the supervision of Peter WOLF and Pacôme DELVA

The official Proceedings of the 5th Galileo Science Colloquium  which took place from the 27th to the 29th of October 2015 at PTB, Braunschweig, Germany are now
available online at:  http://www.congrexprojects.com/2015-events/15a08/proceedings

The Posters/Presentations and/or Papers can be downloaded in PDF format.

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ESA’s LISA Pathfinder lifted off earlier on Thursday, 3rd Dec. on a Vega rocket from Europe’s spaceport in Kourou, French Guiana, on its way to demonstrate technology for observing gravitational waves from space.

 

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Anthony BERCY will defend his PhD thesis , entitled “Ultrastable optical fiber link :  multiple-users dissemination,  study of fundamental and technological limits and new applications”. His thesis work was accomplished within a collaboration between LPL and SYRTE. His thesis grant has been co-funded by FIRST-TF.

 

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The ITU World Radiocommunication Conference (WRC-15), currently in session in Geneva from 2 to 27 November, has decided that further studies are required on the impact and application of a future reference time-scale, including the modification of coordinated universal time (UTC) and suppressing the so-called “leap second”.

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Alexis BONNIN will defend his PhD thesis , entitled “Dual-Species Atom Interferometry and Applications to Inertial Measurements”, which work was accomplished in ONERA . The defense will take place on Monday, 23 of November 2015 at 14:00 in Laboratoire Aimé Cotton (Salle Balmer), Orsay.

Summary :

In the emerging issue of testing the Equivalence Principle with cold atom inertial sensors, this thesis focuses on the realization and the characterization of a simultaneous dual-species atom interferometer (⁸⁷Rb & ⁸⁵Rb) which allows to measure the differential acceleration in an extremely sensitive way. The Mach-Zehnder type atom interferometer relies on the simultaneous handling of atomic wave-packets with stimulated Raman transitions. The laser system is based on the frequency doubling of a single laser source at 1560 nm. All the required laser frequencies for handling both isotopes (trapping, cooling, selection, interferometry and detection) are generated by phase modulating this source. A detailed modeling of the interferometer’s inertial responses and an analysis of a method to extract the differential phase were carried out. The differential acceleration measurement led to an atom based test of the Weak Equivalence Principle of η( ⁸⁷Rb, ⁸⁵Rb) = (1.3 ± 3.2) × 10^{− 7}, at the state-of-the-art. The simultaneous aspect of the experiment allowed to highlight for the first time common mode vibration noise rejection with two different atomic species, a rejection factor of 50 000 being currently achieved. The current performance of the instrument exhibits a sensitivity on the differential acceleration of 1.23 × 10^{− 7} g/sqrt(Hz) and a resolution of 2 × 10^{− 9} g for integration times lower than few hours. Finally, innovative operating modes of dual-species atom interferometers for on-board acceleration measurements are explored.

Fabien Théron will defend his PhD thesis , entitled “Development of a cold atom gravity gradiometer and a telecom doubled laser device for onboard applications”, which work was accomplished in ONERA . The defense will take place on Friday, Friday, 27 of November 2015 at 14:00 in Institut d’Optique Graduate School (Auditorium), Palaiseau.

Summary :

This thesis presents the development of the experimental setup allowing the measurement of two gravity gradient components and the gravity acceleration. These quantities are resulted from the measuring of rubidium cold atoms acceleration, in free fall in vacuum, by atom interferometry. For gradiometry, the differential measurement is realized between two atomic clouds spatially separated. For the measurement of vertical gradient, the use of mobile optical lattices allows to get two atom clouds from a single atomic source.

This work presents the setting up of the complete device, in particular with the built of the vaccum chamber, laser and micro-wave systems. Lasers are based on frequency-doubled telecom technology, which allows to obtain compact and robust systems, dedicated for onboard applications. The innovative laser architecture allows to combine atom interferometry and optical lattices, while minimizing the amount of components. The laser noise has been characterized, and limits the single shot gravimetric sensitivity to 10-9 g, the single shot differential sensitivity to 10-10 g, and the single shot gradiometric sensitivity to 38 E.

Indranil DUTTA will defend his PhD thesis , entitled “Stability Improvement of a Sagnac Cold Atom Interferometer: towards Continuous Operation”, which work was accomplished in SYRTE under the supervision of Arnaud Landragin. The defense will take place on Friday, 20 of November 2015 at 14:30 in Paris Observatory (Salle de l’IAP).

Summary on the thesis work

Valerian Thiel will defend his PhD thesis, , entitled “Modal analysis of an ultrafast frequency comb: from classical to quantum spectral correlations”, which work was accomplished in Laboratoire Kastler Brossel under the supervision of Nicolas Treps. It will take place on Monday the 19^th of October in the amphitheater Herpin, building Esclangon, at Université Pierre et Marie Curie. The defense will be in english.