Related papers: Hyperfine averaging by dynamic decoupling in a mul…
Today's most accurate clocks are based on laser spectroscopy of electronic transitions in single trapped ions and feature fractional frequency uncertainties below $1\times10^{-18}$. Scaling these systems to multiple, simultaneously…
We report on an evaluation of an optical clock that uses the $\phantom{}^2S_{1/2} \rightarrow \phantom{}^2D_{5/2}$ transition of a single $^{88}$Sr$^+$ ion as the reference. In contrast to previous work, we estimate the effective…
We propose and demonstrate a novel detection scheme of clock signals and obtain an ultra-high resonance contrast above 90%. The precision of the signal's detection and the signal-to-noise ratio (SNR) of atomic clock signal is improved…
We demonstrate a weak continuous measurement of the pseudo-spin associated with the clock transition in a sample of Cs atoms. Our scheme uses an optical probe tuned near the D1 transition to measure the sample birefringence, which depends…
We report on the direct observation of resonant electric dipole-dipole interactions in a cubic array of atoms in the many-excitation limit. The interactions, mediated by single-atom couplings to the shared electromagnetic vacuum, are shown…
We report on a frequency measurement of the $(3s^2)^1S_0\to(3s3p)^3P_1$ clock transition of $^{24}$Mg on a thermal atomic beam. The intercombination transition has been referenced to a portable primary Cs frequency standard with the help of…
Ramsey interferometry is a widely used tool for precisely measuring transition frequencies between two energy levels of a quantum system, with applications in time-keeping, precision spectroscopy, quantum optics, and quantum information.…
Light-induced frequency shifts can be a key limiting contribution to the mid and long-term frequency instability in atomic clocks. In this letter, we demonstrate the experimental implementation of the combined error signal interrogation…
Singly-ionized ytterbium, with ultra-narrow optical clock transitions at 467 nm and 436 nm, is a convenient system for the realization of optical atomic clocks and tests of present-day variation of fundamental constants. We present the…
An exact generalization of the Ramsey transition probability is derived to improve ultra-high precision measurement and quantum state engineering when a particle is subjected to independently-tailored separated oscillating fields. The…
Atomic clocks use atomic transitions as frequency references. The susceptibility of the atomic transition to external fields limits clock stability and introduces systematic frequency shifts. Here, we propose to realize an atomic clock that…
Improving the clock stability is of fundamental importance for the development of quantum-enhanced metrology. One of the main limitations arises from the randomly-fluctuating local oscillator (LO) frequency, which introduces "phase slips"…
We investigate the feasibility of precision frequency metrology with large ion crystals. For clock candidates with a negative differential static polarisability, we show that micromotion effects should not impede the performance of the…
We report the first experimental determination of the hyperfine quenching rate of the $6s^2\ ^1\!S_0\ (F=1/2) - 6s6p\ ^3\!P_0\ (F=1/2)$ transition in $^{171}$Yb with nuclear spin $I=1/2$. This rate determines the natural linewidth and the…
The experimental comparison of two thulium optical lattice clocks in a time interval of up to one hour has been carried out. The synchronous comparison of a clock transition in two independent atomic ensembles using a single ultrastable…
Divalent atoms and ions with a singlet $S$ ground state and triplet $P$ excited state form the basis of many high-precision optical atomic clocks. Along with the metastable $^{3}\mathrm{P}_{0}$ clock state, these atomic systems also have a…
The systematic shifts of the transition frequencies in the molecular hydrogen ions are of relevance to ultra-high-resolution radio-frequency, microwave and optical spectroscopy of these systems, performed in ion traps. We develop the…
Ramsey interferometry is routinely used in quantum metrology for the most sensitive measurements of optical clock frequencies. Spontaneous decay to the electromagnetic vacuum ultimately limits the interrogation time and thus sets a lower…
Optical atomic clocks are the most accurate measurement devices ever constructed and have found many applications in fundamental science and technology. The use of highly charged ions (HCI) as a new class of references for highest accuracy…
We present improved constraints on the coupling of ultralight bosonic dark matter to photons based on long-term measurements of two optical frequency ratios. In these optical clock comparisons, we relate the frequency of the ${}^2S_{1/2}…