Fundamental physics with a state-of-the-art optical clock in space

Abstract

Recent advances in optical atomic clocks and optical time transfer have enabled new possibilities in precision metrology for both tests of fundamental physics and timing applications. Here we describe a space mission concept that would place a state-of-the-art optical atomic clock in an eccentric orbit around Earth. A high stability laser link would connect the relative time, range, and velocity of the orbiting spacecraft to earthbound stations. The primary goal for this mission would be to test the gravitational redshift, a classical test of general relativity, with a sensitivity 30,000 times beyond current limits. Additional science objectives include other tests of relativity, enhanced searches for dark matter and drifts in fundamental constants, and establishing a high accuracy international time/geodesic reference.

Gravitational redshift test using Rb clocks of eccentric GPS satellites

“…The development of stabilized femtosecond-laser frequency combs and improvements in laser cooling/trapping techniques in cooperation with advances in atomic quantum systems has led to rapid improvements in clocks at optical frequencies [43] , [44] . Using optical atomic clocks will improve the uncertainty for α to [45] . The ability to directly measure the environmental parameters of clocks [45] , improvements in clock technology [46] , and available SLR corrections for new generations of GNSS satellites, thereby lead to new studies to considerably improve the test in the future.…”

“…Using optical atomic clocks will improve the uncertainty for α to [45] . The ability to directly measure the environmental parameters of clocks [45] , improvements in clock technology [46] , and available SLR corrections for new generations of GNSS satellites, thereby lead to new studies to considerably improve the test in the future.…”

Opportunities for Fundamental Physics Research with Radioactive Molecules

“…Future clock development will allow for many order of magnitude improvements of these experiments. Deployment of high-precision clocks in space is proposed for many applications, including tests of gravity (Derevianko et al, 2022), search for darkmatter halo bound to the Sun (Tsai et al, 2022), and gravitational waves detection in wavelength ranges inaccessible on Earth (Vutha, 2015;Kolkowitz et al, 2016;Fedderke et al, 2021).…”

Quantum Test of the Local Position Invariance with Internal Clock Interferometry

“…It is worthwhile noting the decades of progress in precise atomic clocks [5,6,23,24], optical clocks in space [25][26][27], and matter-wave interferometry [28][29][30][31]. Specifically, we note the recent proposals towards observing visibility modulation with the spatial superposition of clock wave packets [13,14,17,32].…”

“…Thus, it can suppress systematic common noise. Meanwhile, it doesn't suffer from the recombining issue like the usual atom interferometers do, so the setup can be located anywhere with any speed, considering the significant progress with the compact atomic clock in space [25][26][27]. This internal atom interferometer can serve as a precise quantum sensor for tests of local position invariance and measurements of the possible time variation of fundamental constants such as fine-structure constant [11,12].…”