Atomic clock performance beyond the geodetic limit

Abstract

The passage of time is tracked by counting oscillations of a frequency reference, such as Earth's revolutions or swings of a pendulum. By referencing atomic transitions, frequency (and thus time) can be measured more precisely than any other physical quantity, with the current generation of optical atomic clocks reporting fractional performance below the $10^{-17}$ level. However, the theory of relativity prescribes that the passage of time is not absolute, but impacted by an observer's reference frame. Consequently, clock measurements exhibit sensitivity to relative velocity, acceleration and gravity potential. Here we demonstrate optical clock measurements surpassing the present-day ability to account for the gravitational distortion of space-time across the surface of Earth. In two independent ytterbium optical lattice clocks, we demonstrate unprecedented levels in three fundamental benchmarks of clock performance. In units of the clock frequency, we report systematic uncertainty of $1.4\times 10^{-18}$, measurement instability of $3.2\times 10^{-19}$ and reproducibility characterised by ten blinded frequency comparisons, yielding a frequency difference of $[-7\pm (5{)}_{stat}\pm (8{)}_{sys}]\times 10^{-19}$. While differential sensitivity to gravity could degrade the performance of these optical clocks as terrestrial standards of time, this same sensitivity can be used as an exquisite probe of geopotential. Near the surface of Earth, clock comparisons at the $1\times 10^{-18}$ level provide 1 cm resolution along gravity, outperforming state-of-the-art geodetic techniques. These optical clocks can further be used to explore geophysical phenomena, detect gravitational waves, test general relativity and search for dark matter.

32 pages, 5 figures

References in corpus (31)

• Frequency Comparison of Two High-Accuracy Al+ Optical Clocks
• Systematic evaluation of an atomic clock at 2e-18 total uncertainty
• Single-Ion Atomic Clock with $3\times 10^{-18}$ Systematic Uncertainty
• Hunting for topological dark matter with atomic clocks
• Geodesy and metrology with a transportable optical clock
• Searching for dilaton dark matter with atomic clocks
• Gravitational wave detection with optical lattice atomic clocks
• The IAU 2000 resolutions for astrometry, celestial mechanics and metrology in the relativistic framework: explanatory supplement
• Ultra-stable optical clock with two cold-atom ensembles
• A Fermi-degenerate three-dimensional optical lattice clock
• Spectroscopic observation of SU(N)-symmetric interactions in Sr orbital magnetism
• Multipolar theory of black-body radiation shift of atomic energy levels and its implications for optical lattice clocks
• Real-time geopotentiometry with synchronously linked optical lattice clocks
• Searching for an oscillating massive scalar field as a dark matter candidate using atomic hyperfine frequency comparisons
• Test of special relativity using a fiber network of optical clocks
• Frequency ratio of Yb and Sr clocks with $5\times 10^{-17}$ uncertainty at 150 s averaging time
• Nuclear Spin Effects in Optical Lattice Clocks
• Suppression of collisional shifts in a strongly interacting lattice clock
• Search for domain wall dark matter with atomic clocks on board global positioning system satellites
• An atomic clock with $1\times 10^{-18}$ room-temperature blackbody Stark uncertainty
• Dynamic polarizabilities and related properties of clock states of ytterbium atom
• Hyperpolarizability and operational magic wavelength in an optical lattice clock
• p-Wave cold collisions in an optical lattice clock
• Scattering of Cold Atom Coherences by Hot Atoms: Frequency Shifts from Background Gas Collisions
• Observation and cancellation of the dc Stark shift in strontium optical lattice clocks
• Strategies for reducing the light shift in atomic clocks
• Determination of a high spatial resolution geopotential model using atomic clock comparisons
• Delivering pulsed and phase stable light to atoms of an optical clock
• Atomic clocks as a tool to monitor vertical surface motion
• Quenched narrow-line second- and third-stage laser cooling of 40Ca
• Faraday-shielded, DC Stark-free optical lattice clock

Cited by in corpus (218)

• 20 years of developments in optical frequency comb technology and applications
• An ${}^{27}$Al${}^{+}$ quantum-logic clock with systematic uncertainty below $10^{-18}$
• Optical clock intercomparison with $6\times 10^{-19}$ precision in one hour
• Resolving the gravitational redshift within a millimeter atomic sample
• JILA SrI Optical Lattice Clock with Uncertainty of $2.0\times 10^{-18}$
• Optical clock comparison test of Lorentz symmetry
• Matter-wave Atomic Gradiometer Interferometric Sensor (MAGIS-100)
• A clock with $8\times 10^{-19}$ systematic uncertainty
• Improved limits for violations of local position invariance from atomic clock comparisons
• Seconds-scale coherence in a tweezer-array optical clock
• 300 GHz wave with attosecond-level timing noise
• Coherent Optical Clock Down-Conversion for Microwave Frequencies with 10-18 Instability
• ZAIGA: Zhaoshan Long-baseline Atom Interferometer Gravitation Antenna
• Ytterbium nuclear-spin qubits in an optical tweezer array
• High precision differential clock comparisons with a multiplexed optical lattice clock
• Realizing spin squeezing with Rydberg interactions in a programmable optical clock
• Roadmap towards the redefinition of the second
• 113 km Free-Space Time-Frequency Dissemination at the 19th Decimal Instability
• A quantum network of entangled optical atomic clocks
• Near-Unitary Spin Squeezing in ${}^{171}$Yb
• Distributed quantum sensing with a mode-entangled network of spin-squeezed atomic states
• Long-lived Bell states in an array of optical clock qubits
• Multi-qubit gates and Schrödinger cat states in an optical clock
• An atomic array optical clock with single-atom readout
• Quantum Variational Optimization of Ramsey Interferometry and Atomic Clocks
• Quantum-enhanced sensing on an optical transition via emergent collective quantum correlations
• Molecular lattice clock with long vibrational coherence
• Demonstration of a time scale based on a stable optical carrier
• Point-to-Point Stabilised Optical Frequency Transfer with Active Optics
• Quantum Technologies in Space
• Distributed quantum sensing enhanced by continuous-variable error correction
• Enhanced Sensitivity to Ultralight Bosonic Dark Matter in the Spectra of the Linear Radical SrOH
• Search for ultralight dark matter from long-term frequency comparisons of optical and microwave atomic clocks
• Thermodynamics of a deeply degenerate SU($N$)-symmetric Fermi gas
• Narrow-line Cooling and Determination of Magic Wavelength of Cd
• Ultra-stable Free-Space Laser Links for a Global Network of Optical Atomic Clocks
• Lasing on a narrow transition in a cold thermal strontium ensemble
• Heisenberg-limited noisy atomic clock using a hybrid coherent and squeezed states protocol
• Evaluation of lattice light shift at low 10${}^{-19}$ uncertainty for a shallow lattice Sr optical clock
• Ramsey-Bordé matter-wave interferometry for laser frequency stabilization at $10^{-16}$ frequency instability and below
• Towards a Transportable Aluminium Ion Quantum Logic Optical Clock
• Invited Review: Micro-fabricated components for cold atom sensors
• The ${}^{229}$Th isomer: prospects for a nuclear optical clock
• Engineering Quantum States of Matter for Atomic Clocks in Shallow Optical Lattices
• Compact 459 nm Cs cell optical frequency standard with $2.1\times {10}^{-13}/\sqrt{\tau }$ short-term stability
• Hamiltonian engineering of spin-orbit coupled fermions in a Wannier-Stark optical lattice clock
• Optical frequency ratio of a ${}^{171}{\mathrm{Yb}}^{+}$ single-ion clock and a ${}^{87}\mathrm{Sr}$ lattice clock
• Rugged mHz-Linewidth Superradiant Laser Driven by a Hot Atomic Beam
• Cold-atom clock based on a diffractive optic
• The unit of time: present and future directions
• A strontium optical lattice clock with $1\times 10^{-17}$ uncertainty and measurement of its absolute frequency
• Detection of metastable electronic states by Penning trap mass spectrometry
• Stand-alone vacuum cell for compact ultracold quantum technologies
• Continuous guided strontium beam with high phase-space density
• Optical Atomic Clock aboard an Earth-orbiting Space Station (OACESS): Enhancing searches for physics beyond the standard model in space
• A Sideband-Enhanced Cold Atomic Source For Optical Clocks
• Engineering spin squeezing in a 3D optical lattice with interacting spin-orbit-coupled fermions
• Direct comparisons of European primary and secondary frequency standards via satellite techniques
• Concepts for direct frequency-comb spectroscopy of ${}^{229\text{m}}$Th and an internal-conversion-based solid-state nuclear clock
• Absolute frequency measurement of the 171Yb optical lattice clock at KRISS using TAI for over a year
• Suppressing inhomogeneous broadening in a lutetium multi-ion optical clock
• Demonstration of the nearly continuous operation of an ${}^{171}$Yb optical lattice clock for half a year
• Realization of phase locking in good-bad-cavity active optical clock
• Probing Time Dilation in Coulomb Crystals in a high-precision Ion Trap
• The theory of direct laser excitation of nuclear transitions
• A terahertz vibrational molecular clock with systematic uncertainty at the $10^{-14}$ level
• Enhanced observation time of magneto-optical traps using micro-machined non-evaporable getter pumps
• Modeling the electronic structures of the ground and excited states of the ytterbium atom and the ytterbium dimer: A modern quantum chemistry perspective
• Measurements of ${}^{27}$Al${}^{+}$ and ${}^{25}$Mg${}^{+}$ magnetic constants for improved ion clock accuracy
• Advanced light-shift compensation protocol in a continuous-wave microcell atomic clock
• Radium Ion Optical Clock
• Modeling light shifts in optical lattice clocks
• Systematic uncertainty due to background-gas collisions in trapped-ion optical clocks
• Passive Optical Phase Noise Cancellation
• Absolute frequency of ${}^{87}\mathrm{Sr}$ at $1.8\times 10^{-16}$ uncertainty by reference to remote Primary Frequency Standards
• Ab initio quantum theory of mass defect and time dilation in trapped-ion optical clocks
• Probing Multiple Electric Dipole Forbidden Optical Transitions in Highly Charged Nickel Ions
• Optical Atomic Clock Comparison through Turbulent Air
• RydIQule: A Graph-based Paradigm for Modelling Rydberg and Atomic Systems
• 10 GHz Generation with Ultra-Low Phase Noise via the Transfer Oscillator Technique
• Algorithmic Ground-state Cooling of Weakly-Coupled Oscillators using Quantum Logic
• Sub-recoil clock-transition laser cooling enabling shallow optical lattice clocks
• Hyperfine averaging by dynamic decoupling in a multi-ion lutetium clock
• Combined error signal in Ramsey spectroscopy of clock transitions
• Simultaneous two initial clock states preparation for thulium optical clock
• Searching for a Fifth Force with Atomic and Nuclear Clocks
• A mid-infrared magneto-optical trap of metastable strontium for an optical lattice clock
• Rabi Spectroscopy and Sensitivity of a Floquet Engineered Optical Lattice Clock
• Coherent Manipulation of Orbital Feshbach Molecules of Two-Electron Atoms
• Electric dipole matrix elements for the $6p{}^2{P}_J\to 7s{}^2{S}_{1/2}$ transition in atomic cesium
• Blackbody radiation shift for the ${}^1$S${}_0$--${}^3$P${}_0$ optical clock transition in zinc and cadmium atoms
• Observation of a narrow inner-shell orbital transition in atomic erbium at 1299 nm
• Absolute frequency measurement of the 87Sr optical lattice clock at NTSC using International Atomic Time
• Prospects of a Pb${}^{2+}$ ion clock
• Hyperfine constants and line separations for the ${}^1{S}_0-{}^3{P}_1$ intercombination line in neutral ytterbium with sub-Doppler resolution
• Cavity-enhanced non-destructive detection of atoms for an optical lattice clock
• The ${}^1{\mathrm{S}}_0$-${}^3{\mathrm{P}}_2$ magnetic quadrupole transition in neutral strontium
• Global Time Distribution via Satellite-Based Sources of Entangled Photons
• All-passive multiple-place optical phase noise cancellation
• Fano-like resonance due to interference with distant transitions
• Demonstration of a Mobile Optical Clock Ensemble at Sea
• A New Clock Transition with the Highest Sensitivity to $\alpha$ Variation and Simultaneous Magic Trapping Conditions with Other Clock Transitions in Yb
• Improved Frequency Ratio Measurement with 87Sr and 171Yb Optical Lattice Clocks at NMIJ
• Quadruply Ionized Barium as a Candidate for a High-Accuracy Optical Clock
• Coherent suppression of tensor frequency shifts through magnetic field rotation
• Dipole-dipole frequency shifts in multilevel atoms
• Branching optical frequency transfer with enhanced post automatic phase noise cancellation
• Trap-induced ac Zeeman shift of the thorium-229 nuclear clock frequency
• Multi-node optical frequency dissemination with post automatic phase correction
• Testing the Einstein Equivalence Principle with two Earth-orbiting clocks
• Relativistic tidal effects on clock-comparison experiments
• Absolute frequency measurement of a Yb optical clock at the limit of the Cs fountain
• MCDHF-CI calculations for Hg and Cd with estimates for unknown clock transition frequencies
• Modeling motional energy spectra and lattice light shifts in optical lattice clocks
• Optical Telecommunications-Band Clock based on Neutral Titanium Atoms
• Dynamic multipolar polarizabilities and hyperpolarizabilities of the Sr lattice clock
• Atomic clocks highly sensitive to the variation of the fine structure constant based on Hf II, Hf IV, and W VI ions
• High-accuracy optical clocks based on group 16-like highly charged ions
• Precision measurements with cold atoms and trapped ions
• A steady-state magneto-optical trap of fermionic strontium on a narrow-line transition
• Magic polarization for light shift cancellation in two-photon optical clocks
• A Review of Contemporary Atomic Frequency Standards
• Passive Optical Phase Stabilization on a Ring Fiber Network
• Cavity-immune features in the spectra of superradiant crossover laser pulses
• Novel repumping on ${}^3$P${}_0$$\to$${}^3$D${}_1$ for Sr magneto-optical trap and Landé g factor measurement of ${}^3$D${}_1$
• State-dependent potentials for the ${}^1{\text{S}}_0$ and ${}^3{\text{P}}_0$ clock states of neutral ytterbium atoms
• Excited-Band Coherent Delocalization for Improved Optical Lattice Clock Performance
• Clock precision beyond the Standard Quantum Limit at $10^{-18}$ level
• Cryogenic Optical Lattice Clock with $1.7\times 10^{-20}$ Blackbody Radiation Stark Uncertainty
• Observations of coherence de Broglie waves
• The concept of laser-based conversion electron Mössbauer spectroscopy for a precise energy determination of ${}^{229m}$Th
• A cavity-enhanced broadband photonic Rabi oscillation
• Fully digital platform for local ultra-stable optical frequency distribution
• Demonstration of chronometric leveling using transportable optical clocks beyond laser coherence limit
• Influence of cosmological expansion in local experiments
• Clock-line-mediated Sisyphus Cooling
• Preliminary Sensitivity Study for a Gravitational Redshift Measurement with China's Lunar Exploration Project
• A simple, powerful diode laser system for atomic physics
• Improved absolute clock stability by the joint interrogation of two atomic states
• Classical and Quantum Frequency Combs for Satellite-based Clock Synchronization
• Gravitational influence of high power laser pulses
• Dissipative pure-optical trap for laser cooling and trapping of neutral atoms
• Generation of a precise time scale assisted by a near-continuously operating optical lattice clock
• A laser with instability reaching $4\times 10^{-17}$ based on a 10-cm-long silicon cavity at sub-5-K temperatures
• High-fidelity imaging of a band insulator in a three-dimensional optical lattice clock
• Current-feedback-stabilized laser system for quantum simulation experiments using Yb clock transition at 578 nm
• Losses of thulium atoms from optical dipole traps operating at 532 and 1064 nm
• Evaluation of the blackbody radiation shift of an Yb optical lattice clock at KRISS
• Absolute frequency measurements with a robust, transportable ^{40}Ca^{+} optical clock
• Ultra-stable transportable ultraviolet clock laser using cancellation between photo-thermal and photo-birefringence noise
• Hundred-Femtosecond-Level Concise Optical Time Delay Measurement System Based on Linear Optical Sampling
• Be optical lattice clocks with the fractional Stark shift up to the level of 10${}^{-19}$
• Magic intensity trapping of the Mg lattice clock with light shift suppressed below $10^{-19}$
• Toward a quantum-enhanced strontium optical lattice clock at INRIM
• Accurate laser frequency locking to optical frequency combs under low-signal-to-noise-ratio conditions
• Testing screened scalar-tensor theories of gravity with atomic clocks
• An optical atomic clock using $4D_J$ states of rubidium
• Trapping ${}^{171}$Yb Atoms into a One-Dimensional Optical Lattice with a Small Waist
• Observation of the $4f^{14}6s^2{}^1{S}_0-4f^{13}5d6s^2(J=2)$ clock transition at 431 nm in ${}^{171}$Yb
• Open-Loop Polarization Mode Dispersion Mitigation for Fibre-Optic Time and Frequency Transfer
• Node-downloadable frequency transfer system based on a mode-locked laser with over 100 km of fiber
• Studies of thorium and ytterbium ion trap loading from laser ablation for gravity monitoring with nuclear clocks
• Evaluation of the relativistic redshift in frequency standards at KRISS
• Searching for New Fundamental Interactions via Isotopic Shifts in Molecular Lattice Clocks
• Ratchet Loading and Multi-Ensemble Operation in an Optical Lattice Clock
• Ramsey-Borde atom interferometry with a thermal strontium beam for a compact optical clock
• Wavefront Curvature in Optical Atomic Beam Clocks
• Robust frequency stabilization and linewidth narrowing of a laser with large intermittent frequency jumps using an optical cavity and an atomic beam
• Theoretical Calculation of the Quadratic Zeeman Shift Coefficient of the 3P0 clock state for Strontium Optical Lattice Clock
• Synchronous Comparison of Two Thulium Optical Clocks
• Bose-Einstein condensate as a diagnostic tool for an optical lattice formed by 1064 nm laser light
• Reexamination of the ground state Born-Oppenheimer Yb${}_2$ potential
• Accurate Determination of Blackbody Radiation Shifts in a Strontium Molecular Lattice Clock
• Towards Adoption of an Optical Second: Verifying Optical Clocks at the SI Limit
• Probe field ellipticity-induced shift in an atomic clock
• Demonstration of Real-Time Precision Optical Time Synchronization in a True Three-Node Architecture
• Enhancing optical lattice clock coherence times with erasure conversion
• Cold Atoms in Space: Community Workshop Summary and Proposed Road-Map
• Ground state EIT cooling of ${}^{171}$Yb${}^{+}$ ion
• Limitation of single-repumping schemes for laser cooling of Sr atoms
• Quantum Sensing Using Atomic Clocks for Nuclear and Particle Physics
• Analyzing the optical pumping on the $5s4d{}^1{D}_2-5s8p{}^1{P}_1$ transition in a magneto-optical trap of Sr atoms
• Absolute frequency measurement of a Lu${}^{+}$ ${(}^3{\mathrm{D}}_1)$ optical frequency standard via link to international atomic time
• Precision magnetometry exploiting excited state quantum phase transitions
• Improved absolute frequency measurement of ${}^{171}$Yb at NMIJ with uncertainty below $2\times 10^{-16}$
• Blackbody Radiation Noise Broadening of Quantum Systems
• Simulation of optical lattice trap loading from a cold atomic ensemble
• Noise-induced servo errors in optical clocks utilizing Rabi interrogation
• Collinear Three-Photon Excitation of a Strongly Forbidden Optical Clock Transition
• Single-atom imaging of ${}^{173}$Yb in optical tweezers loaded by a five-beam magneto-optical trap
• Relativistic theory for time and frequency transfer through flowing media with an application to the atmosphere of Earth
• Superradiant active optical atomic clocks: motivations and current challenges
• A symmetry-protected topological optical lattice clock
• The permanent tide and the International Height Reference Frame IHRF
• High-Power, Fiber-Laser-Based Source for Magic-Wavelength Trapping in Neutral-Atom Optical Clocks
• Robust optical frequency transfer in a noisy urban fiber network
• A plug-and-play solution for characterizing two-way optical frequency transfer over free-space
• Decoherence of Atomic Ensembles in Optical Lattice Clocks by Gravity
• From ultra-noisy to ultra-stable: optimization of the optoelectronic laser lock
• Direct loading of a Sr magneto-optical trap from a thermal atomic beam
• A Brillouin Laser Optical Atomic Clock
• International Optical Clock Comparison Using the European Optical Fiber Network
• A High-frequency Geodetic VLBI Experiment for Optical Clock Comparison
• 100-ns-level timing holdover after 12 years for rubidium atomic fountains
• Investigating the $4D_{3/2}|3,\pm 2⟩$--$4D_{5/2}|3,\pm 2⟩$ transition in Nb${}^{4+}$ for a THz atomic clock
• Generating 500 mW for laser cooling of strontium atoms by injection locking a high power laser diode
• Improving the Q factor of an optical atomic clock using quantum non-demolition measurement
• Prospects for optical clocks combining high sensitivity to new physics with insensitivity to perturbations; the case of Sb${}^{+}$, Au${}^{+}$, and Hg${}^{2+}$
• Extraordinary low systematic frequency shifts in bi-colour thulium optical clock
• Determining geopotential difference via relativistic precise point positioning time comparison: A case study using simulated observations
• Redshift Duality with Pantheon+SH0ES in a Planck-anchored Flat $\Lambda$CDM Framework: Implications for Hubble Tension and Observational Inference
• Low-frequency fiber-optic vibration sensing with a Floquet-engineered optical lattice clock
• Direct Measurement of the $5s5p{}^1{P}_1\to 5s4d{}^1{D}_2$ Decay Rate in Strontium
• Unification of global height system at centimeter level using precise frequency signal links
• Preliminary experimental results of determining the geopotential difference between two synchronized portable hydrogen clocks at different locations
• Preliminary characterization of a surface electrode Paul trap for frequency metrology
• Resolution of the paradox of the diamagnetic effect on the Kibble coil
• Sub-Doppler cooling, state preparation, and optical trapping of a triel atom