pith. sign in

arxiv: 2606.10514 · v1 · pith:2ZNVODRZnew · submitted 2026-06-09 · ⚛️ physics.atom-ph

Ytterbium lattice clock with uncertainty of 1.1times 10⁻¹⁸ and instability of low 10⁻¹⁹

Qiang Zhu , Jingran Shi , Yuechen Zhang , Xiatian Xu , Bing Wang , Dezhi Xiong , Zhuanxian Xiong , Pengcheng Fang
show 3 more authors
Qunfeng Chen Lingxiang He Baolong Lyu
This is my paper

Pith reviewed 2026-06-27 11:12 UTC · model grok-4.3

classification ⚛️ physics.atom-ph
keywords ytterbiumoptical lattice clocksystematic uncertaintyblackbody radiation shiftfrequency comparisonatomic clock stability
0
0 comments X

The pith

An ytterbium optical lattice clock reaches total systematic uncertainty of 1.1×10^{-18}.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper presents an optical lattice clock based on 171Yb atoms that achieves a total systematic uncertainty of 1.1×10^{-18}. Differential frequency comparisons between two nominally identical clocks are used to evaluate and reduce shifts from lattice light, blackbody radiation, and other sources. An in-vacuum buildup cavity boosts lattice power while a vacuum BBR shield provides a controlled thermal environment. Synchronous operation yields a stability of 2.7×10^{-19} after 216000 seconds of averaging. The magic lattice frequency is fixed at 394798258.3(1) MHz and the two clocks are intended for remote comparisons between Shanghai and Wuhan.

Core claim

The authors establish an ytterbium lattice clock with total systematic uncertainty of 1.1×10^{-18} through differential measurements between two identical systems, in-vacuum lattice enhancement, and a shielded BBR environment that limits the blackbody contribution to 8.7×10^{-19}.

What carries the argument

Differential frequency measurement between two identical clocks, which isolates and quantifies systematic shifts by direct subtraction.

If this is right

  • Lattice light shift uncertainty is held to 3×10^{-19} under typical conditions.
  • BBR Stark shift uncertainty is limited to 8.7×10^{-19} by the vacuum shield.
  • The two clocks support direct remote frequency comparisons between Shanghai and Wuhan.
  • Magic frequency is determined to 394798258.3(1) MHz with 0.1 MHz uncertainty.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The differential method could be extended to test whether common-mode environmental drifts remain below the 10^{-19} level over longer baselines.
  • Achieved stability suggests the clock could resolve small secular drifts in fundamental constants if operated continuously for months.
  • Scaling the twin-clock approach to additional sites would enable a network with sub-10^{-18} consistency for geodetic or relativistic tests.

Load-bearing premise

That frequency differences measured between the two clocks capture every systematic effect without residual common-mode errors from shared environment or unmodeled couplings.

What would settle it

An observed frequency offset between the two clocks that exceeds the stated 1.1×10^{-18} total uncertainty after all listed corrections are applied.

Figures

Figures reproduced from arXiv: 2606.10514 by Baolong Lyu, Bing Wang, Dezhi Xiong, Jingran Shi, Lingxiang He, Pengcheng Fang, Qiang Zhu, Qunfeng Chen, Xiatian Xu, Yuechen Zhang, Zhuanxian Xiong.

Figure 1
Figure 1. Figure 1: Physics package and optical scheme of the Yb2 lattice clock. (a) Three-dimensional drawing of the vacuum system. The main components are marked. A BBR shield (not shown) is installed inside the science chamber. (b) Optical scheme for the science chamber. The directions of magnetic field, gravity orientation, and polarizations of the clock and lattice lasers are indicated. (c) Schematic of the vertically or… view at source ↗
Figure 2
Figure 2. Figure 2: (a) Longitudinal sideband spectra at 173 Er before (blue line) and after (red line) sideband cooling. The 16- ms sideband cooling reduces the longitudinal temperature from 1.9 µK to 0.8 µK, corresponding to a mean longitudinal motional number ⟨nz⟩ = 0.04. (b) A typical single-scan, 800-ms Rabi spectrum of the 1S0- 3P0 clock transition; the red line is a free￾parameter sinc2 function fit [PITH_FULL_IMAGE:f… view at source ↗
Figure 3
Figure 3. Figure 3: (a) Time sequence for synchronized and antisynchronized Rabi spectroscopy. (b) Measured instability of a Yb OLC. Total Allan deviation represents the single￾clock measurement instability, 1/ √ 2 (ν2 − ν1) /νclock. The blue and red datasets use synchronized Rabi spectroscopy. The magenta set uses anti-synchronized Rabi spectroscopy. The lines represent the white frequency noise asymptotes. For red dataset, … view at source ↗
Figure 4
Figure 4. Figure 4: (a) Solidworks rendering of the in-vacuum BBR shield. The black arrows represent the direction of the atomic beam. For scale, the flange is 6.75 inches in diameter. (b) Image of a platinum RTD embedded in a copper bolt that can be screwed into the copper body of the BBR shield. (c) Image of the black-coated copper sphere with a platinum RTD inside. This thermal probe was placed at the center of the BBR shi… view at source ↗
Figure 5
Figure 5. Figure 5: Temporal variation of the temperature difference between the spherical probe and the BBR shield. The spherical probe is placed at the position of the atoms. Statistical averaging of these data yields −7.1 mK with a standard error of 2.8 mK [PITH_FULL_IMAGE:figures/full_fig_p005_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: Fractional density shift per N0 atoms as a function of the lattice trap depth U (black dots). These data are fit to κU3/2 (red solid line), yielding a scaling factor κ = −4.95(16) × 10−22 . The shaded area indicates the 1σ confidence band on the fit. the lattice laser frequency νl in the following form α ∗ (νl) = ∂α∗ ∂νl (νl − νzero), and it vanishes at νzero. Note that νzero represents an effective magic … view at source ↗
Figure 7
Figure 7. Figure 7: (a) Lattice light shifts as a function of lattice depth. Colored dots represent data sets with distinct detunings of νl relative to the reference frequency 394 798 266.9 MHz. Solid lines represent global fits with the thermal model. (b) Linear coefficient α ∗ from the global fit as a function of the detuning of νl . The solid line is a linear fit. 3.4. Other systematic effects Zeeman shift. We had measured… view at source ↗
read the original abstract

We report an optical lattice clock based on $^{171}$Yb atoms with a total systematic uncertainty of $1.1\times 10^{-18}$. In-vacuum buildup cavity was employed to enhance the lattice light power. Differential frequency measurement between two identical clocks facilitate the evaluation of systematic shifts. Synchronous comparison of the two clocks reached a stability level of $2.7\times 10^{-19}$ in an averaging time of 216,000 s. The magic frequency $\nu_{\mathrm{zero}}$ was determined to be 394 798 258.3(1) MHz. Under typical operating conditions, the lattice light shift is controlled at an uncertainty level of $3\times 10^{-19}$. The blackbody radiation (BBR) shield which is placed in vacuum provides a well-characterized BBR environment, enabling an uncertainty contribution of $8.7\times 10^{-19}$ from the BBR Stark shift. Other systematic shifts have also been evaluated. The two clocks will be used for remote frequency comparisons between Shanghai and Wuhan.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 2 minor

Summary. The paper reports an optical lattice clock based on 171Yb atoms achieving a total systematic uncertainty of 1.1×10^{-18}. It employs an in-vacuum buildup cavity to enhance lattice light power and uses differential frequency measurements between two identical clocks to evaluate systematic shifts. The magic frequency is determined as 394798258.3(1) MHz, with lattice light shift uncertainty controlled at 3×10^{-19} and BBR Stark shift uncertainty at 8.7×10^{-19} via a vacuum BBR shield. Synchronous comparison yields a stability of 2.7×10^{-19} at 216000 s averaging time. The clocks are intended for remote frequency comparisons between Shanghai and Wuhan.

Significance. If the uncertainty evaluations hold, this represents a competitive precision level for Yb lattice clocks, advancing optical frequency standards and enabling applications in fundamental constant tests and long-baseline comparisons. The differential measurement protocol and hardware elements (buildup cavity, BBR shield) are standard strengths that support the quoted low contributions from lattice and BBR shifts.

major comments (2)
  1. [Abstract] Abstract: The total systematic uncertainty of 1.1×10^{-18} is stated alongside BBR (8.7×10^{-19}) and lattice (3×10^{-19}) contributions, but without an explicit uncertainty budget table or section detailing all individual terms, their evaluation methods, and the combination rule (e.g., root-sum-square), the total cannot be independently verified from the provided information.
  2. [Abstract] Abstract: The central claim relies on differential frequency measurements between two nominally identical clocks to isolate and quantify all systematic shifts; however, the assumption that this protocol fully eliminates residual common-mode errors or unaccounted environmental couplings lacks quantitative bounds or tests in the evaluation description, which is load-bearing for the 1.1×10^{-18} total.
minor comments (2)
  1. [Abstract] The magic frequency is reported as 394 798 258.3(1) MHz; clarify the exact meaning of the parenthetical uncertainty and ensure consistent notation throughout.
  2. Consider including a summary table of all evaluated systematic shifts with references to the relevant measurement sections for improved clarity.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the careful review and constructive comments. We address the two major comments point by point below.

read point-by-point responses

  1. Referee: [Abstract] Abstract: The total systematic uncertainty of 1.1×10^{-18} is stated alongside BBR (8.7×10^{-19}) and lattice (3×10^{-19}) contributions, but without an explicit uncertainty budget table or section detailing all individual terms, their evaluation methods, and the combination rule (e.g., root-sum-square), the total cannot be independently verified from the provided information.

    Authors: The abstract is necessarily concise. The complete uncertainty budget table, listing every individual term with its evaluated value, method of determination, and the root-sum-square combination yielding the total 1.1×10^{-18}, appears in the main text (Systematic Uncertainty Evaluation section). We will revise the abstract to include an explicit cross-reference to this table so that readers can locate the full details immediately. revision: yes

  2. Referee: [Abstract] Abstract: The central claim relies on differential frequency measurements between two nominally identical clocks to isolate and quantify all systematic shifts; however, the assumption that this protocol fully eliminates residual common-mode errors or unaccounted environmental couplings lacks quantitative bounds or tests in the evaluation description, which is load-bearing for the 1.1×10^{-18} total.

    Authors: Quantitative bounds on residual common-mode rejection and environmental couplings are derived from the synchronous comparison data and auxiliary monitoring channels; these bounds and the associated tests are presented in the Differential Measurement and Systematic Shift Evaluation sections of the manuscript. The quoted total uncertainty incorporates these bounds. revision: no

Circularity Check

0 steps flagged

No significant circularity

full rationale

The paper's central result is an experimental uncertainty budget for a Yb lattice clock obtained via differential frequency comparisons between two nominally identical systems. The magic frequency, lattice shift, and BBR contributions are reported as direct measurements or characterizations (e.g., ν_zero = 394798258.3(1) MHz, lattice uncertainty 3×10^{-19}, BBR 8.7×10^{-19}), not as outputs of a model fitted to the final uncertainty figure. No self-citation chain, ansatz smuggling, or uniqueness theorem is invoked to close the derivation; the evaluation protocol is standard and externally falsifiable through the quoted stability and parameter-variation data. The derivation chain therefore remains self-contained against external benchmarks.

Axiom & Free-Parameter Ledger

1 free parameters · 1 axioms · 0 invented entities

The central claim rests on experimental determination of the magic frequency and the assumption that the listed systematic evaluations are complete and independent; no new entities postulated.

free parameters (1)
  • magic frequency = 394798258.3(1) MHz
    Experimentally located zero-shift point at 394798258.3(1) MHz; value is measured rather than derived from first principles.
axioms (1)
  • domain assumption The two clocks are sufficiently identical that differential measurements isolate all relevant systematic shifts.
    Invoked to justify the stability and uncertainty evaluation method described in the abstract.

pith-pipeline@v0.9.1-grok · 5762 in / 1282 out tokens · 24063 ms · 2026-06-27T11:12:45.824120+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

44 extracted references

  1. [1]

    Ushijima I, Takamoto M, Das M, Ohkubo T and Katori H 2015Nature Photonics9185–189

  2. [2]

    Huntemann N, Sanner C, Lipphardt B, Tamm C and Peik E 2016Phys. Rev. Lett.116(6) 063001

  3. [3]

    McGrew W F, Zhang X, Fasano R J, Sch¨ affer S A, Beloy K, Nicolodi D, Brown R C, Hinkley N, Milani G, Schioppo M, Yoon T H and Ludlow A D 2018Nature56487–90

  4. [4]

    Ohmae N, Takamoto M, Takahashi Y, Kokubun M, Araki K, Hinton A, Ushijima I, Muramatsu T, Furumiya T, Sakai Y, Moriya N, Kamiya N, Fujii K, Muramatsu R, Shiimado T and Katori H 2021Advanced Quantum Technologies42100015

  5. [5]

    Huang Y, Zhang B, Zeng M, Hao Y, Ma Z, Zhang H, Guan H, Chen Z, Wang M and Gao K 2022Phys. Rev. Applied 17034041

  6. [6]

    Cui K, Chao S, Sun C, Wang S, Zhang P, Wei Y, Yuan J, Cao J, Shu H and Huang X 2022Eur. Phys. J. D76140

  7. [7]

    Tofful A, Baynham C F A, Curtis E A, Parsons A O, Robertson B I, Schioppo M, Tunesi J, Margolis H S, Hendricks R J, Whale J, Thompson R C and Godun R M 2024Metrologia61045001

  8. [8]

    Ma Z Y, Deng K, Wang Z Y, Wei W Z, Hao P, Zhang H X, Pang L R, Wang B, Wu F F, Liu H L, Yuan W H, Chang J L, Zhang J X, Wu Q Y, Zhang J and Lu Z H 2024Phys. Rev. Appl.21(4) 044017

  9. [9]

    Liao T Y, Liu H, Meng F, Wang Q, Yang T, Tian H C, Lu B K, Zhu L, Li Y, Lin B K, Fang Z J and Lin Y G 2025 Chinese Physics Letters42034201

    2025

  10. [10]

    Lu X T, Guo F, Liu Y Y, Cao J, Li J A, Xia J J, Xu Q F, Lu B Q, Wang Y B and Chang H 2025Metrologia62 035007

  11. [11]

    Zhang T, Jin T, Qi Q, Lei S, Xia Y, Zhang J, Chang H, Feng S, Liu X, Wang J, Zhang R, Xu Z, Tang Z and Xu X 2026Metrologia63025004

  12. [12]

    Brewer S M, Chen J S, Hankin A M, Clements E R, Chou C W, Wineland D J, Hume D B and Leibrandt D R 2019 Phys. Rev. Lett.123(3) 033201

    2019

  13. [13]

    Zhiqiang Z, Arnold K J, Kaewuam R and Barrett M D 2023 Science Advances9eadg1971

    2023

  14. [14]

    Aeppli A, Kim K, Warfield W, Safronova M S and Ye J 2024Phys. Rev. Lett.133(2) 023401

  15. [15]

    Marshall M C, Castillo D A R, Arthur-Dworschack W J, Aeppli A, Kim K, Lee D, Warfield W, Hinrichs J, Nardelli N V, Fortier T M, Ye J, Leibrandt D R and Hume D B 2025Phys. Rev. Lett.135(3) 033201

  16. [16]

    Lindvall T, Fordell T, Hanhij¨ arvi K, Doleˇ zal M, Rahm J, Weyers S and Wallin A 2025Phys. Rev. Appl.24(4) 044082

  17. [17]

    Zhang B l, Ma Z x, Huang Y, Han H l, Hu R m, Wang Y z, Zhang H q, Tang L y, Shi T y, Guan H and Gao K l 2026 Phys. Rev. Lett.136(5) 053202

    2026

  18. [18]

    Jia Z P, Li J, Kong D Q, Zhang X, Yu H W, Liu X Y, Zhang Y C, Wang Y B, Zhu X Q, Zhang J H, Zhu M Y, Feng P J, Cui X Y, Xu P, Jiang X, Liu X P, Liu P, Dai H N, Chen Y A and Pan J W 2026Metrologia63025002

  19. [19]

    Dimarcq N, Gertsvolf M, Mileti G, Bize S, Oates C W, Peik E, Calonico D, Ido T, Tavella P, Meynadier F, Petit G, Panfilo G, Bartholomew J, Defraigne P, Donley E A, Hedekvist P O, Sesia I, Wouters M, Dub´ e P, Fang F, Levi F, Lodewyck J, Margolis H S, Newell D, Slyusarev S, Weyers S, Uzan J P, Yasuda M, Yu D H, Rieck C, Schnatz H, Hanado Y, Fujieda M, Pott...

  20. [20]

    Ido T, Hachisu H, Nakagawa F and Hanado Y 2016Journal of Physics: Conference Series723012041

  21. [21]

    Grebing C, Al-Masoudi A, D¨ orscher S, H¨ afner S, Gerginov V, Weyers S, Lipphardt B, Riehle F, Sterr U and Lisdat C 2016Optica3563–569

  22. [22]

    Hachisu H, Nakagawa F, Hanado Y and Ido T 2018 Scientific Reports84243

    2018

  23. [23]

    Yao J, Sherman J, Fortier T, Leopardi H, Parker T, Levine J, Savory J, Romisch S, McGrew W, Zhang X, Nicolodi 10 D, Fasano R, Sch¨ affer S, Beloy K and Ludlow A 2018 NAVIGATION65601–608

    2018

  24. [24]

    Kobayashi T, Akamatsu D, Hosaka K, Hisai Y, Wada M, Inaba H, Suzuyama T, Hong F L and Yasuda M 2020 Metrologia57065021

    2020

  25. [25]

    Zhu L, Wang Q, Wang Y, Lin Y, Yang D, Li Y, Yang T, Meng F, Lin B, Tian H, Lu B and Fang Z 2024 Measurement Science and Technology35125014

    2024

  26. [26]

    Yuan Y, Cao J, Yuan J, Wang D, Fang P, Chen Q, Cao S, Wang X, Chao S, Shu H, Li G, Xu J, Fu G, Yang Y, Zhao R, Shi F and Huang X 2026Metrologia63025003

  27. [27]

    Nosske I, Vishwakarma C, L¨ ucke T, Rahm J, Poudel N, Weyers S, Benkler E, D¨ orscher S and Lisdat C 2025 Quantum Science and Technology10045076

    2025

  28. [28]

    Oelker E, Hutson R B, Kennedy C J, Sonderhouse L, Bothwell T, Goban A, Kedar D, Sanner C, Robinson J M, Marti G E, Matei D G, Legero T, Giunta M, Holzwarth R, Riehle F, Sterr U and Ye J 2019Nature Photonics13 714–719

  29. [29]

    Liu X Y, Liu P, Li J, Zhang Y C, Wang Y B, Jia Z P, Zhang X, Zhu X Q, Kong D Q, Song W L, Niu G Z, Yang Y M, Feng P J, Liu X P, Cui X Y, Xu P, Jiang X, Yin J, Liao S K, Peng C Z, Dai H N, Chen Y A and Pan J W 2025 Phys. Rev. Lett.135(26) 263402

    2025

  30. [30]

    Beloy K, Hinkley N, Phillips N B, Sherman J A, Schioppo M, Lehman J, Feldman A, Hanssen L M, Oates C W and Ludlow A D 2014Phys. Rev. Lett.113(26) 260801

  31. [31]

    Xu Y L and Xu X Y 2016Chinese Physics B25103202

  32. [32]

    Xiong D, Zhu Q, Wang J, Zhang A, Tian C, Wang B, He L, Xiong Z and Lyu B 2021Metrologia58035005

  33. [33]

    Heo M S, Kim H, Yu D H, Lee W K and Park C Y 2022 Metrologia59055002

    2022

  34. [34]

    Yu H, Liu P, Li Y, Jia Z, Zhang X, Yan J, Li J, Dai H and Chen Y 2026Measurement257118527 ISSN 0263-2241

  35. [35]

    Hassan Y S, Beloy K, Siegel J L, Kobayashi T, Swiler E, Grogan T, Brown R C, Rojo T, Bothwell T, Hunt B D, Halaoui A and Ludlow A D 2025Phys. Rev. Lett.135(6) 063402

  36. [36]

    Brown R C, Phillips N B, Beloy K, McGrew W F, Schioppo M, Fasano R J, Milani G, Zhang X, Hinkley N, Leopardi H, Yoon T H, Nicolodi D, Fortier T M and Ludlow A D 2017Phys. Rev. Lett.119(25) 253001

  37. [37]

    Zhang A, Xiong Z, Chen X, Jiang Y, Wang J, Tian C, Zhu Q, Wang B, Xiong D, He L, Ma L and Lyu B 2022 Metrologia59065009

    2022

  38. [38]

    Sherman J A, Lemke N D, Hinkley N, Pizzocaro M, Fox R W, Ludlow A D and Oates C W 2012Phys. Rev. Lett. 108(15) 153002

  39. [39]

    Dzuba V A and Derevianko A 2010Journal of Physics B: Atomic, Molecular and Optical Physics43074011

  40. [40]

    Bothwell T, Hunt B D, Siegel J L, Hassan Y S, Grogan T, Kobayashi T, Gibble K, Porsev S G, Safronova M S, Brown R C, Beloy K and Ludlow A D 2025Phys. Rev. Lett.134(3) 033201

  41. [41]

    Zhang A, Tian C, Zhu Q, Wang B, Xiong D, Xiong Z, He L and Lyu B 2023Chinese Physics B32020601

  42. [42]

    Beloy K, Zhang X, McGrew W F, Hinkley N, Yoon T H, Nicolodi D, Fasano R J, Sch¨ affer S A, Brown R C and Ludlow A D 2018Phys. Rev. Lett.120(18) 183201

  43. [43]

    Fasano R, Chen Y, McGrew W, Brand W, Fox R and Ludlow A 2021Phys. Rev. Appl.15(4) 044016

  44. [44]

    Jia Z P, Cui X Y, Xie Y J, Zhang X, Niu G Z, Liu X Y, Zhu Q Q, Li J and Dai H N 2025Phys. Rev. Appl.23(1) 014014