General presentation of the project

The applications of MIGA extend from monitoring the evolution of the Earth gravitational field to providing a new tool for detecting gravitational waves. By combining geophysics and fundamental physics application in a single infrastructure, MIGA will lead to an unprecedented step in understanding geophysical phenomena and will allow for extending the low frequency sensitivity of future gravitational wave detectors. It will keep France among the leaders in many major fields; fundamental physics, matter wave interferometry, geophysics and gravitational wave astronomy.

The MIGA project was selected in December 2011 by the French National Research Agency (ANR) as a large scale excellence instrument. The project is coordinated by the LP2N laboratory at Institut d’Optique d’Aquitaine (Talence).

MIGA principle

The AI geometry of MIGA is similar to the one of a Mach-Zenhder Interferometer for optical waves. This concept is described in the Figure below (left) where matter waves are manipulated by a set of counterpropagating laser pulses. At the entrance of the interferometer, a pulse creates an equiprobable coherent superposition of states of the manipulated atoms. The matter-waves are then deflected by the use of pulse before being recombined with a second pulse. To realize these beam-splitters and mirror pulses, MIGA will make use of Bragg diffraction of matter-waves on light standing waves. Conservation of energy-momentum during this process imposes to couple only atomic states of momentum to state where k is the wave vector of the interrogation field. At the output of the interferometer, the transition probability between these states is obtained by a two waves interference formula . The atom phase shift depends on the laser phase difference which is imprinted on the diffracted matter-wave during the interrogation process.

Left: principle of aMach Zenhder interferometer for matter-waves. Right: geometry of the MIGA antenna combining a set of AIs interrogated inside an optical cavity.

MIGA will make use of a set of such AIs interrogated by the resonant field of an optical cavity. In this configuration, each AI will measures the inertial effects along the cavity axis at position together with GW effects associated to the cavity propagation of the interrogation laser.

Cold atom source

The atom source unit delivers cold atom clouds which will be interrogated by the MIGA cavity Bragg beams to form the atom interferometer (AI). The general design of the unit is presented in the Figure below. Its main functions are (i) the loading and laser cooling of 87Rb atoms, (ii) the launching of the atomic cloud along a quasi-vertical trajectory and the control of the angle of the trajectory with respect to the cavity beams, (iii) the preparation of the cold atom source before it enters the interferometer, and (iv) the detection of the atoms at the interferometer output.

Global view of the cold atom source unit

The MIGA consortium

The MIGA project involves 15 French laboratories and 3 companies expert in atomic physics, optics, geophysics, hydrology and instrumentation. The MIGA instrument will be installed at the Low Noise underground Laboratory LSBB in the South-East of France.

Within the MIGA consortium, SYRTE is in charge of the coordination of the atom interferometry activities. SYRTE realizes the cold atom sources which will be the core of the antenna, and studies advanced atom interferometry techniques to improve the sensitivity of MIGA.

Status

The five cold atom preparation units have been produced and tested.

The infrastructure for the project (rooms and tunnels in LSBB) is ready.

Perspectives

The installation of the instrument in the tunnel in LSBB has started. Vacuum tests are being performed. The next important step is to put the 150 m long tube under high vacuum.

The MIGA team at SYRTE

• Quentin Beaufils, CNRS research engineer
• Remi Geiger, Associate Professor at Sorbonne Université
• David Holleville, CNRS research engineer
• Bertrand Venon, CNRS engineer
• Arnaud Landragin, CNRS research director
• Former members: Louis Amand (2013-2016, mechanical engineer); Thomas Chantrait (2016-2017, mechanical engineer)

Related Publications

Cold-atom sources for the Matter-wave laser Interferometric Gravitation Antenna (MIGA)
Beaufils, Q., Sidorenkov, L.A., Lebegue, P. et al. Cold-atom sources for the Matter-wave laser Interferometric Gravitation Antenna (MIGA). Sci Rep 12, 19000 (2022). https://doi.org/10.1038/s41598-022-23468-3

Exploring gravity with the MIGA large scale atom interferometer
MIGA collaboration
Scientific Reports volume 8, Article number: 14064 (2018)

Future Gravitational Wave Detectors Based on Atom Interferometry
Remi Geiger
arXiv:1611.09911
book "An Overview of Gravitational Waves: Theory and Detection", edited by G. Auger and E. Plagnol (World Scientific, 2017)

Low frequency gravitational wave detection with ground-based atom interferometer arrays
W. Chaibi, R. Geiger, B. Canuel, A. Bertoldi, A. Landragin, and P. Bouyer
Phys. Rev. D 93, 021101(R), 2016

Matter-wave laser Interferometric Gravitation Antenna (MIGA): New perspectives for fundamental physics and geosciences
R. Geiger, L. Amand, A. Bertoldi, B. Canuel, W. Chaibi, C. Danquigny, I. Dutta, B. Fang, S. Gaffet, J. Gillot, D. Holleville, A. Landragin, M. Merzougui, I. Riou, D. Savoie, P. Bouyer
arXiv:1505.07137

The matter-wave laser interferometer gravitation antenna (MIGA): New perspectives for fundamental physics and geosciences
B. Canuel, L. Amand, A. Bertoldi, W. Chaibi, R. Geiger, J. Gillot, A. Landragin, M. Merzougui, I. Riou, S.P. Schmid and P. Bouyer
E3S Web of Conferences, Volume 4, 01004 (2014) i-DUST 2014 – Inter-Disciplinary Underground Science & Technology.

Links

MIGA website

MIGA brief description (French)

Funding