Related papers: Advanced Satellite-based Frequency Transfer at the…

8-Gsps 1-bit Analog-to-Digital Converters (ADCs) were newly developed toward the realization of the wideband observation. The development of the wideband ADCs is one of the most essential developments for the radio interferometer. To…

We present the new absolute frequency measurement of ytterbium (171Yb) obtained at INRiM with the optical lattice clock IT-Yb1 against the cryogenic caesium (133Cs) fountain IT-CsF2, evaluated through a measurement campaign that lasted 14…

Atomic clocks have been transformational in science and technology, leading to innovations such as global positioning, advanced communications, and tests of fundamental constant variation. Next-generation optical atomic clocks can extend…

Optical lattice clocks with uncertainty and instability in the $10^{-17}$-range and below have so far been demonstrated exclusively using fermions. Here, we demonstrate a bosonic optical lattice clock with $3\times 10^{-18}$ instability and…

High-precision optical pulse trains distribution via fibre links has made huge impacts in many fields. In most published works, the accuracies are still fundamentally limited by some unavoidable noises, such as thermal and shot noise from…

High-precision pulsar timing observations are limited in their accuracy by the jitter noise that appears in the arrival time of pulses. Therefore, it is important to systematically characterise the amplitude of the jitter noise and its…

We review our progress in developing a frequency reference with singly ionized lutetium and give estimates of the levels of inaccuracy we expect to achieve in the near future with both the $^1S_0\leftrightarrow{}^3D_1$ and…

It is widely recognised that over-reliance on GNSS (e.g GPS) for time synchronisation represents an acute threat to modern society, and a diversity of alternatives are required to mitigate the threat of an outage. This paper proposes a GNSS…

We report on a frequency ratio measurement of a ${}^{199}$Hg-based optical lattice clock referencing a ${}^{87}$Sr-based clock. Evaluations of lattice light shift, including atomic-motion-dependent shift, enable us to achieve a total…

We present the 3-5 $\mu$m transmission spectrum of HD 15337 c (TOI-402.02), a sub-Neptune (2.526 R$_{\oplus}$, 6.792 M$_{\oplus}$, T$_{\rm eq}$$\sim$656 K) around a K1V star observed as part of the JWST COMPASS program. We reduce these…

We performed an absolute frequency measurement of the $^1S_{0}$-$^3P_{0}$ transition in $^{87}$Sr with a fractional uncertainty of $1.2 \times 10^{-15}$, which is less than one third that of our previous measurement. A caesium fountain…

The projected systematic uncertainties of single trapped Ytterbium-ion optical frequency standards are estimated for the quadrupole and octupole transitions which are at wavelengths 435.5 nm and 467 nm, respectively. Finite temperature 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…

A high performance Space-Time Reference in orbit could be realized using a stable atomic clock in a precisely defined orbit and linking that to high accuracy atomic clocks on the ground using a laser based time-transfer link. This would…

We have carried absolute frequency measurements of the $(6s^{2})\,^{1}S_{0}$ $-$ $(6s6p)\,^{3}P_{1}$ transition in $^{171}$Yb (the intercombination line), where the spin-1/2 isotope yields two hyperfine lines. The measurements rely on…

From 1979--1996 the Green Bank Interferometer was used by the Naval Research Laboratory to monitor the flux density from 146 compact radio sources at frequencies near 2 and 8 GHz. We filter the ``light curves'' to separate intrinsic…

Optical lattice clocks surpass primary Cs microwave clocks in frequency stability and accuracy, and are promising candidates for a redefinition of the second in the International System of Units (SI). However, the robustness of optical…

A satellite-based scheme to perform clock synchronization between ground stations spread across the globe using quantum resources was proposed in [Phys. Rev. A 107, 022615 (2023)], based on the quantum clock synchronization (QCS) protocol…

Satellite quantum communications have rapidly evolved in the past few years, culminating in the proposal, development, and deployment of satellite missions dedicated to quantum key distribution and the realization of fundamental tests of…

We used GTC instrument OSIRIS to obtain long-slit spectra in the optical range (520-1040 nm) of the planetary host star WASP-43 (and a reference star) during a full primary transit event and four partial transit observations. We integrated…