Related papers: Optical Clocks in Space
Clock synchronization is the backbone of applications such as high-accuracy satellite navigation, geolocation, space-based interferometry, and cryptographic communication systems. The high accuracy of synchronization needed over…
Time and frequency are the most accurately measurable quantities, providing foundations for science and modern technologies. The accuracy relies on the SI (Syst\'eme International) second that refers to Cs microwave clocks with fractional…
The successful miniaturisation of extremely accurate atomic clocks and atom interferometers invites prospects for satellite missions to perform precision experiments. We discuss the effects predicted by general relativity and alternative…
A global network of optical atomic clocks will enable unprecedented measurement precision in fields including tests of fundamental physics, dark matter searches, geodesy, and navigation. Free-space laser links through the turbulent…
There has been tremendous progress in the performance of optical frequency standards since the first proposals to carry out precision spectroscopy on trapped, single ions in the 1970s. The estimated fractional frequency uncertainty of…
An orbiting `photon clock' is proposed to test directly the relativity of simultaneity of special relativity. This is done by comparison of the arrival times at a ground station of three microwave signals transmitted by two satellites…
All experiments to date are in remarkable agreement with the predictions of Einstein's theory of gravity, General Relativity. Besides the classical tests, involving light deflection, orbit precession, signal delay, and the gravitational…
Good clocks are of importance both to fundamental physics and for applications in astronomy, metrology and global positioning systems. In a recent technological breakthrough, researchers at NIST have been able to achieve a stability of 1…
This article develops a protocol to synchronize clocks on board a network of satellites equipped with quantum resources. We show that, in such a constellation, satellites reinforce each other's sync capabilities, forming a common clock that…
Pulsars are remarkably precise "celestial clocks" that can be used to explore many different aspects of physics and astrophysics. In this article I give a brief summary of pulsar properties and describe some of the applications of pulsar…
Precise time scale is the universal base for all measurements. Here we report the deployment of a compact and transportable optical clock to a timekeeping institution and steering an active hydrogen maser to generate an optical time scale,…
Considering the OPERA neutrino-velocity measurement from the point of view of a GPS satellite we find that the detector at Gran Sasso has a velocity component in the order of $10^{-5}c$ towards the neutrino emission location at CERN. On…
The transfer of high-quality time-frequency signals between remote locations underpins a broad range of applications including precision navigation and timing, the new field of clock-based geodesy, long-baseline interferometry, coherent…
Our spacetime is filled with gravitational wave backgrounds that constitute a fluctuating environment created by astrophysical and cosmological sources. Bounds on these backgrounds are obtained from cosmological and astrophysical data but…
We present a transportable optical clock (TOC) with $^{87}$Sr. Its complete characterization against a stationary lattice clock resulted in a systematic uncertainty of ${7.4 \times 10^{-17}}$ which is currently limited by the statistics of…
The exquisite control exhibited over quantum states of individual particles has revolutionized the field of precision measurement, as exemplified by the most accurate atomic clock realized in single trapped ions. Whereas many-atom lattice…
Atomic clock technology is advancing rapidly, now reaching stabilities of $\Delta f/f \sim 10^{-18}$, which corresponds to resolving $1$ cm in equivalent geoid height over an integration timescale of about 7 hours. At this level of…
We propose a Doppler tracking system for gravitational wave detection via Double Optical Clocks in Space (DOCS). In this configuration two spacecrafts (each containing an optical clock) are launched to space for Doppler shift observations.…
We derive the predicted time dilation of delocalized atomic clocks in an optical lattice setup in the presence of a gravitational field to leading order in quantum relativistic corrections. We investigate exotic quantum states of motion…
In this paper, a hypothesis that the cosmological gravitational potential can be measured with the use of high-precision atomic clocks is proposed and substantiated. The consideration is made with the use of a quasi-classical description of…