Spectroscopy and frequency measurement of the⁸⁷Sr clock transition by laser linewidth transfer using an optical frequency comb

Abstract

In the hole-doped, high-temperature superconducting cuprates, an intrinsic heterogeneity is found, from the early observations to recent data. Below optimum doping, the heterogeneity consists of dynamic metallic and, at low temperatures, superconducting regions in the form of clusters or stripes, which develop and decay as a function of time and location in the antiferromagnetic lattice. This behaviour is underlined by the interesting linear relation between the oxygen isotope shifts of the magnetic penetration depth and the critical temperature with a slope that is a factor 2 larger than expected for the homogeneous distribution of superfluid density. Allusion is also made to the Bose-Einstein condensation reported in structurally heterogeneous, polycrystalline polymer platelets as well as especially to the heterogeneous distribution of visible and dark matter in the Universe, which point to a change of paradigm in modern physics. perspective

Frequency ratio measurement of ^171Yb and ^87Sr optical lattice clocks

“…The frequency ratio of the -15 . The uncertainty of the frequency ratio measurement is more than twice smaller than that of the absolute frequency measurements using the TAI link in our institutes [11,12]. The obtained frequency ratio of Yb and Sr agrees with the calculated value using the previously reported absolute frequency measurements [6,13].…”

“…In relation to redefining the second, absolute frequency measurements of optical lattice clocks have been reported from several institutes at the 10 -15 -10 -16 uncertainty level [6][7][8][9][10][11][12][13][14]. The measurement uncertainty is limited by the current frequency standards that realize the definition of the second.…”

Towards the optical second: verifying optical clocks at the SI limit

“…*ssr+ah*sah+rb*srb+sensm 120))+dmu*(x-58305)/365.225)+sensq 0))+dq*(x-58305)/365.225)+sensalph* 120))+dalph*(xA summary of this work, as well as six other Yb absolute frequency measurements (yellow)[18,[27][28][29][30][31], and seventeen Sr measurements (red)[9,10,[34][35][36][37][38][39][40][41][42][43][44][45][46][47][48].Sr measurements are multiplied by the Yb/Sr ratio and the error bars are expanded as descibed in the main text. The fit function (orange) constrains possible variation of the Yb/Cs ratio, and the shaded region represents the 1σ uncertainty of the fit.…”

Horloges à réseau optique au strontium

“…9). Enfin, les premières comparaisons tout optique entre les horloges à réseau optique au strontium et au mercure LNE-SYRTE [26,35], le JILA (Colorado, États-unis) [36,37], la PTB (Allemagne) [29,30,38], l'Université de Tokyo (Japon) en 2006 et 2008 [39], le NICT (Japon) [40][41][42], le NMIJ (Japon) [43,44] et le NIM en 2015 (Chine) [45]. Un ajustement de ces mesures par une dérive linéaire dans le temps superposée à une variation sinusoïdale d'amplitude a calée sur la rotation de la Terre autour du soleil permet de contraindre la dérive du rapport de fréquence par d ln(ν Sr /ν Cs )/dt = −(1, 7 ± 0, 7) × 10 conduites au LNE-SYRTE permettent de s'affranchir des étalons micro-onde, et ainsi de démontrer une stabilité de fréquence dix fois meilleure, à quelques 10 −15 / √ τ.…”