Measuring absolute frequencies beyond the GPS limit via long-haul optical frequency dissemination.

Global Positioning System (GPS) dissemination of frequency standards is ubiquitous at present, providing the most widespread time and frequency reference for the majority of industrial and research applications worldwide. On the other hand, the ultimate limits of the GPS presently curb further advances in high-precision, scientific and industrial applications relying on this dissemination scheme. Here, we demonstrate that these limits can be reliably overcome even in laboratories without a local atomic clock by replacing the GPS with a 642-km-long optical fiber link to a remote primary caesium frequency standard. Through this configuration we stably address the 1S0-3P0 clock transition in an ultracold gas of 173Yb, with a precision that exceeds the possibilities of a GPS-based measurement, dismissing the need for a local clock infrastructure to perform beyond-GPS high-precision tasks. We also report an improvement of two orders of magnitude in the accuracy on the transition frequency reported in literature.

[1]  Andrew J. Daley,et al.  Quantum computing and quantum simulation with group-II atoms , 2011, Quantum Inf. Process..

[2]  M. Zucco,et al.  High-accuracy coherent optical frequency transfer over a doubled 642-km fiber link , 2014, 1404.0395.

[3]  C W Oates,et al.  Observation and absolute frequency measurements of the 1S0-3P0 optical clock transition in neutral ytterbium. , 2005, Physical review letters.

[4]  L. Livi,et al.  Strongly Interacting Gas of Two-Electron Fermions at an Orbital Feshbach Resonance. , 2015, Physical review letters.

[5]  Christian Chardonnet,et al.  Ultra-stable long distance optical frequency distribution using the Internet fiber network and application to high-precision molecular spectroscopy , 2012, Optics express.

[6]  M. Wilde,et al.  Optical Atomic Clocks , 2019, 2019 URSI Asia-Pacific Radio Science Conference (AP-RASC).

[7]  Wei Zhang,et al.  An optical lattice clock with accuracy and stability at the 10−18 level , 2013, Nature.

[8]  Jun Ye,et al.  Optical atomic clocks , 2014, 1407.3493.

[9]  Christian Chardonnet,et al.  Quantum cascade laser frequency stabilization at the sub-Hz level , 2015 .

[10]  Davide Calonico,et al.  Gravitational redshift at INRIM , 2007 .

[11]  Leo W. Hollberg,et al.  Frequency evaluation of the doubly forbidden 1S0→3P0 transition in bosonic 174Yb , 2008 .

[12]  L. Hollberg,et al.  Frequency evaluation of the doubly forbidden $^1S_0\to ^3P_0$ transition in bosonic $^{174}$Yb , 2008, 0803.4503.

[13]  Davide Calonico,et al.  Planar-waveguide external cavity laser stabilization for an optical link with 10-19 frequency stability , 2011, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[14]  S. Folling,et al.  Observation of two-orbital spin-exchange interactions with ultracold SU(N)-symmetric fermions , 2014, Nature Physics.

[15]  Ying Li,et al.  Direct Comparison of Distant Optical Lattice Clocks at the 10-16 Uncertainty , 2011, 1108.2774.

[16]  P. Zoller,et al.  Two-orbital SU(N) magnetism with ultracold alkaline-earth atoms , 2009, 0905.2610.

[17]  Federico Perini,et al.  A coherent fiber link for very long baseline interferometry , 2015, IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control.

[18]  Paul A. Williams,et al.  High-stability transfer of an optical frequency over long fiber-optic links , 2008 .

[19]  F. Schäfer,et al.  A one-dimensional liquid of fermions with tunable spin , 2014, Nature Physics.

[20]  Tobias Wilken,et al.  Precision measurement of the hydrogen 1S-2S frequency via a 920-km fiber link. , 2013, Physical review letters.

[21]  C W Oates,et al.  High-accuracy measurement of atomic polarizability in an optical lattice clock. , 2011, Physical review letters.

[22]  D. Calonico,et al.  Realization of an ultrastable 578-nm laser for an Yb lattice clock , 2012, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[23]  Davide Calonico,et al.  Accuracy evaluation of ITCsF2: a nitrogen cooled caesium fountain , 2014 .

[24]  Riccardo Barzaghi,et al.  Refining the estimate of the Italian quasi-geoid , 2007 .

[25]  A. Bjerhammar,et al.  On a relativistic geodesy , 1985 .

[26]  D. Calonico,et al.  Accuracy evaluation of ITCsF2: a nitrogen cooled caesium fountain , 2014 .

[27]  A. Ludlow,et al.  An Atomic Clock with 10–18 Instability , 2013, Science.

[28]  P. Zoller,et al.  Spectroscopic observation of SU(N)-symmetric interactions in Sr orbital magnetism , 2014, Science.

[29]  M. Cazalilla,et al.  Ultracold Fermi gases with emergent SU(N) symmetry , 2014, Reports on progress in physics. Physical Society.

[30]  R. Yamazaki,et al.  An SU(6) Mott insulator of an atomic Fermi gas realized by large-spin Pomeranchuk cooling , 2012, Nature Physics.

[31]  Theodor W. Hänsch,et al.  Optical frequency transfer over a single-span 1840 km fiber link , 2013, CLEO 2013.

[32]  Peng Zhang,et al.  Orbital Feshbach Resonance in Alkali-Earth Atoms. , 2015, Physical review letters.

[33]  L. Livi,et al.  Direct observation of coherent interorbital spin-exchange dynamics. , 2014, Physical review letters.

[34]  P. Zoller,et al.  Observation of chiral edge states with neutral fermions in synthetic Hall ribbons , 2015, Science.

[35]  Michael A. Lombardi,et al.  The Use of GPS Disciplined Oscillators as Primary Frequency Standards for Calibration and Metrology Laboratories , 2008 .

[36]  I. Bloch,et al.  Observation of an Orbital Interaction-Induced Feshbach Resonance in (173)Yb. , 2015, Physical review letters.

[37]  Massimo Inguscio,et al.  Light and the distribution of time , 2015 .

[38]  N Quintin,et al.  A clock network for geodesy and fundamental science , 2016, Nature communications.

[39]  P. Zoller,et al.  Quantum computing with alkaline-Earth-metal atoms. , 2008, Physical review letters.

[40]  Manoj Das,et al.  Cryogenic optical lattice clocks , 2015, Nature Photonics.

[41]  Tetsuya Ido,et al.  All-optical link for direct comparison of distant optical clocks. , 2011, Optics express.

[42]  M. Pizzocaro,et al.  A compact ultranarrow high-power laser system for experiments with 578 nm ytterbium clock transition. , 2015, The Review of scientific instruments.

[43]  Marcin Lipiński,et al.  Absolute measurement of the 1S0 − 3P0 clock transition in neutral 88Sr over the 330 km-long stabilized fibre optic link , 2015, Scientific Reports.

[44]  Jieping Ye,et al.  A quantum network of clocks , 2013, Nature Physics.