Test of Lorentz Invariance at the 1 x 10-18 level with optical resonators
Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
Final Report Abstract
In this work, we have demonstrated a significant improvement in the sensitivity of our previously developed apparatus. This was achieved by improving the optical setup and by reducing certain systematic effects such as tilt, angular rotation speed variations and RAM variations. This led to reduction of the statistical uncertainties of the SME coefficients by at least two times, while also reducing the number of rotations by 8 times, compared to our previous work and comparable or in the same order of magnitude as in other works, but with 11 times fewer rotations and a ~ 30 times shorter data acquisition time span respectively. This is a very promising starting point for an extended measurement campaign. Additionally, we present the characterization of two new cavities. The new cavities consist of two 300 mm long ULE spacers in independent vacuum chambers. The measured finesses are 540 000 and 280 000 respectively. Optimization of the spacer design has led to a low vibration sensitivity in the order of 2×10^−10 /g. Because of these properties and the expected reduction of the thermal noise limit by a factor of 3.5 (due to the 3.5 times longer spacer), these cavities are a good candidates for replacing the previous cavity block. We can expect a significant further increase in the apparatus’ sensitivity and accuracy because (1) the lower thermal noise and (2) the smaller cavity linewidth will reduce the effect of imperfections, such as RAM variations in time. We are currently conceiving the plan how the new cavities can be integrated into the previous rotation apparatus.
Publications
- "A compact, robust, and transportable ultra-stable laser with a fractional frequency instability of 1 × 10^−15" Rev. Sci. Instrum. 85, 113107 (2014)
Chen, Q.; Nevsky, A.; Cardace, M.; Schiller, S.; Legero, T.; Häfner, S.; Uhde, A. & Sterr, U.
(See online at https://doi.org/10.1063/1.4898334) - “High-sensitivity crossed-resonator laser apparatus for improved tests of Lorentz invariance and of space-time fluctuations” Phys. Rev. D 93, 022003 (2016)
Chen, Q.; Magoulakis, E. & Schiller, S.
(See online at https://doi.org/10.1103/PhysRevD.93.022003)
