Determination of the Newtonian Gravitational Constant Using Atom Interferometry

Abstract

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.

Squeezed-light-enhanced atom interferometry below the standard quantum limit

“…Atom interferometry is a leading precision measurement technology, having demonstrated state-of-the-art measurements of accelerations and rotations [1][2][3][4][5][6], gravity gradients [7,8], magnetic fields [9], the fine structure constant (α) [10,11], and Newton's gravitational constant (G) [12][13][14][15]. Further increases to the sensitivity of atom interferometers would allow for some exciting science, such as improved tests of the weak equivalence principle [16][17][18], searches for quantum gravitational effects [19], and the measurement of gravitational waves [20,21].…”

Noise-Immune Conjugate Large-Area Atom Interferometers

“…[1], a 3 parts per billion (ppb) modulation in local gravity leads to a 1% shift of the interference fringe. They thus make excellent microscopes for small signals that have been applied in many cutting-edge precision measurements [1][2][3][4][5][6][7][8][9][10]. Large-momentum transfer (LMT) beam splitters, which have become practical recently [11], promise to increase the sensitivity further, by factors of 10s to 100s, by increasing the space-time area enclosed between the interferometer arms.…”

Quantum-projection-noise-limited interferometry with coherent atoms in a Ramsey-type setup

“…Bose-Einstein condensates have been extensively used to simulate lattice effects in solid state physics [4][5][6], to investigate dipolar quantum gases [7] and to show Anderson localization of matter waves [8,9], to mention only a few. Regarding atom interferometry [10], however, the most remarkable results have been so far achieved using thermal atoms, e. g. for the measurement of the gravitational constant G [11,12], the fine structure constant α [13,14] and for the definition of time in atomic clocks [15,16]. Bose-Einstein condensates and the coherent beams or pulses derived from them, known as atom lasers, offer a compelling alternative to thermal sources.…”