Related papers: Tests of relativity using a microwave resonator
We present the design and first measurement results for an ultra-stable cryogenically cooled optical sapphire resonator system with a potential relative frequency stability better than 3x10^-17. This level of oscillator stability allows for…
A recent experiment by Antonini et. al. [Phys. Rev. A {\bf 71}, 050101R 2005], set new limits on Lorentz violating parameters in the frame-work of the photon sector of the Standard Model Extension (SME), $\tilde{\kappa}_{e-}^{ZZ}$, and the…
We report on the evaluation of microwave frequency synthesis using two cryogenic sapphire oscillators developed at the University of Western Australia. A down converter is used to make comparisons between microwave clocks at different…
We present an improved laboratory test of Lorentz invariance in electrodynamics by testing the isotropy of the speed of light. Our measurement compares the resonance frequencies of two orthogonal optical resonators that are implemented in a…
A new ether-drift experiment in D\"usseldorf is currently measuring the relative frequency shift of two cryogenic optical resonators upon active rotations of the apparatus. I point out that the observed fractional amplitude of the sidereal…
We report on the measurement and characterization of power to frequency conversion in the resonant mode of a cryogenic sapphire loaded cavity resonator, which is used as the frequency discriminating element of a loop oscillator circuit.…
We conduct frequency comparisons between a state-of-the-art strontium optical lattice clock, a cryogenic crystalline silicon cavity, and a hydrogen maser to set new bounds on the coupling of ultralight dark matter to Standard Model…
We report observations of the Schawlow-Townes noise limit in a cryogenic sapphire secondary frequency standard. The effect causes a fundamental limit to the frequency stability, and was measured through the novel excitation of a bimodal…
The Cryogenic Sapphire Oscillator is today recognized for its unprecedented frequency stability, mainly coming from the exceptional physical properties of its resonator made in a high quality sapphire crystal. With these instruments, the…
We studied noise properties of microwave signals transmitted through the cryogenic resonator. The experiments were performed with the 11.342 GHz sapphire loaded cavity resonator cooled to 6.2 K. Based on the measured transmission…
We have developed an apparatus to search for the higher-order Lorentz violation in photons by measuring the resonant frequency difference between two counterpropagating directions of an asymmetric optical ring cavity. From the year-long…
We report on a new experiment that tests for a violation of Lorentz invariance (LI), by searching for a dependence of atomic transition frequencies on the orientation of the spin of the involved states (Hughes-Drever type experiment). The…
A simplified form of a nonsymmetric metric is used to develop the coupling of the electrostatic and gravitational fields, which only occurs in dynamic solutions. The coupling results in a resonance in an object near the Schwarzschild…
Phase compensated optical fiber links enable high accuracy atomic clocks separated by thousands of kilometers to be compared with unprecedented statistical resolution. By searching for a daily variation of the frequency difference between…
Levitation of a magnet by superconductor has been an active area of research to explore the quantum mechanical phenomenon. One of the techniques used is to measure the levitation of a magnet placed inside the superconducting microwave…
We compare the long-term fractional frequency variation of four hydrogen masers that are part of an ensemble of clocks comprising the National Institute of Standards and Technology,(NIST), Boulder, timescale with the fractional frequencies…
A new method of probing Lorentz invariance in the neutron sector is described. The method is baed on stable quartz bulk acoustic wave oscillators compared on a rotating table. Due to Lorentz-invariance violation, the resonance frequencies…
Lorentz symmetry is a foundational property of modern physics, underlying the standard model of particles and general relativity. It is anticipated that these two theories are low energy approximations of a single theory that is unified and…
A new experiment to test for the time independence of the fine structure constant, alpha, is proposed. The experiment utilizes orthogonally polarized Transverse Electric and Transverse Magnetic Whispering Gallery Modes in a single sapphire…
Searching for a modified dispersion relation is one of the general relativity tests performed by the LIGO-Virgo-KAGRA collaboration with each new cumulative Gravitational Wave Transient Catalog (GWTC). It considers classes of theories that…