Fig. 3: Data acquired over a period of 912 h with an up-time of 591 h.

a The measured value of κ_LV (blue data points) extracted from the retrieved population P_f. Data points are binned at 15 min intervals. The error bars reflect the standard error (1σ) from quantum projection noise. The data is fitted to Eq. (5) (red line) from which bounds are set on components of the c_MN tensor. b The residuals of the fit with a reduced χ² = 0.92. c A Lomb–Scargle periodogram for spectral analysis of irregularly spaced data. The normalized power spectral density is plotted for frequencies between 0 and 100 μHz. The vertical lines indicate the sidereal day frequency, ω_⊕, (red) and its second harmonic, 2ω_⊕, (blue). The dashed lines indicate the statistical significance level, i.e. p-value, of the peaks³⁶. d The Allan deviation, σ_κ, of the data points shown in a as a function of averaging time, τ. The error bars correspond to the standard error of the stability. From a fit (gray line) to the data, the stability is extracted to be σ_κ = 372(9) mrad s⁻¹ τ^−1/2. The expected stability from quantum projection noise (dashed-dotted green line) is 29(3)% lower.