Reply to ``Comment on `Test of constancy of speed of light with rotating cryogenic optical resonators' ''

An improved analysis of the Michelson-Morley-type experiment by P. Antonini et al. (Phys. Rev. A. 71, 050101 (2005)) yields the Robertson-Mansouri-Sexl theory parameter combination $\beta-\delta-1/2=(-0.6\pm 2.1\pm 1.2)\cdot10^{-10}$ and the Standard Model Extension theory parameter $(\tilde{\kappa}_{e-})^{ZZ} = (-2.9\pm 2.2)\cdot 10^{-14}$.Comment: 2 page

An experiment to detect gravity at sub-mm scale with high-Q mechanical oscillators

Silicon double paddle oscillators are well suited for the detection of weak forces because of their high Q factor (about 10^5 at room temperature). We describe an experiment aimed at the detection of gravitational forces between masses at sub-mm distance using such an oscillator. Gravitational excitation is produced by a rotating aluminium disk with platinum segments. The force sensitivity of this apparatus is about 10 fN at room temperature for 1000 s averaging time at room temperature. The current limitations to detection of the gravitational force are mentioned.Comment: 19 pages, to appear in Proceedings of the Tenth Marcel Grossmann Meeting on General Relativity, edited by M. Novello, S. Perez-Bergliaffa and R. Ruffini, World Scientific. Revision: portable format and revised figure

Ellipsoidal Coulomb Crystals in a Linear Radiofrequency Trap

A static quadrupole potential breaks the cylindrical symmetry of the effective potential of a linear rf trap. For a one-component fluid plasma at low temperature, the resulting equilibrium charge distribution is predicted to be an ellipsoid. We have produced laser-cooled Be$^+$ ellipsoidal ion crystals and found good agreement between their shapes and the cold fluid prediction. In two-species mixtures, containing Be$^+$ and sympathetically cooled ions of lower mass, a sufficiently strong static quadrupole potential produces a spatial separation of the species.Comment: 4 pages, 3 figure

Test of constancy of speed of light with rotating cryogenic optical resonators

A test of Lorentz invariance for electromagnetic waves was performed by comparing the resonance frequencies of two optical resonators as a function of orientation in space. In terms of the Robertson-Mansouri-Sexl theory, we obtain $\beta-\delta-1/2=(+0.5\pm 3\pm 0.7) E-10$, a ten-fold improvement compared to the previous best results. We also set a first upper limit for a so far unknown parameter of the Standard Model Extension test theory, $|(\tilde{\kappa}_{e-})^{ZZ}| < 2\cdot E-14$.Comment: 4 pages, 2 figures, accepted for publication Phys. Rev. A (2005