About 300 experiments tried to determine the value of the Newtonian gravitational constant G to date but large discrepancies in the results prevent from knowing its value precisely 1 . The weakness of the gravitational interaction and the impossibility of shielding the effects of gravity make it very difficult to measure G keeping systematic effects under control. Most of the experiments performed so far were based on the torsion pendulum or torsion balance scheme as in the experiment by Cavendish 2 in 1798 and in all cases they used macroscopic masses.Here we report on the first precise determination of G using laser-cooled atoms and quantum interferometry to probe gravity. We obtain the value G= 6.67191(99) × 10 −11 m 3 kg −1 s −2with a relative uncertainty of 150 ppm. Our value is at 1.5 combined standard deviations from the current recommended value of the Committee on Data for Science and Technology (CODATA) 3 . Such a conceptually different experiment is important to identify the so far elusive systematic errors thus improving the confidence in the value of G. There is no definitive relationship indeed between G and the other fundamental constants and no theoretical pre-1 diction for its value to test the experimental results. Improving the knowledge of G has not only a pure metrological interest, but is also important for the key role that this fundamental constant plays in theories of gravitation, cosmology, particle physics, astrophysics, and geophysical models.The basic idea of our experiment is to use an atom interferometer as gravity sensor and a well-characterized mass as source of a gravitational field. From the precise measurement of the atoms' acceleration produced by the source mass and from the knowledge of the mass distribution, it is possible to extract the value of the gravitational constant G using the well-known formulaAtom interferometers 4, 5 are new tools for experimental gravitation as, for example, in precision measurements of gravity acceleration 6 and gravity gradients 7 , as gyroscopes based on the Sagnac effect 8 , for testing the 1/r 2 law 9 , general relativity 10 and quantum gravity models 11 , and for applications in geophysics 12 . Proof-of-principle experiments to measure G using atom interferometry were reported [13][14][15] . Ongoing studies show that future experiments in space will allow to take full advantage of the potential sensitivity of atom interferometers for fundamental physics tests 16 .The possibility of using atom interferometry for gravitational waves detection is being studied 17 .Since the problem in the determination of G depends on the presence of unidentified systematic errors, our experiment was designed with a double-differential configuration in order to be as immune as possible from such effects: the atomic sensor was a double interferometer in a gravity-2 gradiometer configuration, in order to subtract common-mode spurious signals, and we used two sets of well-characterized tungsten masses as source of the gravitational field that were placed in t...

We propose in this White Paper a concept for a space experiment using cold atoms to search for ultra-light dark matter, and to detect gravitational waves in the frequency range between the most sensitive ranges of LISA and the terrestrial LIGO/Virgo/KAGRA/INDIGO experiments. This interdisciplinary experiment, called Atomic Experiment for Dark Matter and Gravity Exploration (AEDGE), will also complement other planned searches for dark matter, and exploit synergies with other gravitational wave detectors. We give examples of the extended range of sensitivity to ultra-light dark matter offered by AEDGE, and how its gravitational-wave measurements could explore the assembly of super-massive black holes, first-order phase transitions in the early universe and cosmic strings. AEDGE will be based upon technologies now being developed for terrestrial experiments using cold atoms, and will benefit from the space experience obtained with, e.g., LISA and cold atom experiments in microgravity.KCL-PH-TH/2019-65, CERN-TH-2019-126

We present the MIGA experiment, an underground long baseline atom interferometer to study gravity at large scale. The hybrid atom-laser antenna will use several atom interferometers simultaneously interrogated by the resonant mode of an optical cavity. The instrument will be a demonstrator for gravitational wave detection in a frequency band (100 mHz–1 Hz) not explored by classical ground and space-based observatories, and interesting for potential astrophysical sources. In the initial instrument configuration, standard atom interferometry techniques will be adopted, which will bring to a peak strain sensitivity of at 2 Hz. This demonstrator will enable to study the techniques to push further the sensitivity for the future development of gravitational wave detectors based on large scale atom interferometers. The experiment will be realized at the underground facility of the Laboratoire Souterrain à Bas Bruit (LSBB) in Rustrel–France, an exceptional site located away from major anthropogenic disturbances and showing very low background noise. In the following, we present the measurement principle of an in-cavity atom interferometer, derive the method for Gravitational Wave signal extraction from the antenna and determine the expected strain sensitivity. We then detail the functioning of the different systems of the antenna and describe the properties of the installation site.

We present a new measurement of the Newtonian gravitational constant G based on cold-atom interferometry. Freely falling samples of laser-cooled rubidium atoms are used in a gravity gradiometer to probe the field generated by nearby source masses. In addition to its potential sensitivity, this method is intriguing as gravity is explored by a quantum system. We report a value of G = 6.667 x 10(-11) m(3) kg(-1) s(-2), estimating a statistical uncertainty of +/-0.011 x 10(-11) m(3) kg(-1) s(-2) and a systematic uncertainty of +/-0.003 x 10(-11) m(3) kg(-1) s(-2). The long-term stability of the instrument and the signal-to-noise ratio demonstrated here open interesting perspectives for pushing the measurement accuracy below the 100 ppm level.