Sven Herrmann

Modern Michelson-Morley Experiment using Cryogenic Optical Resonators

We report on a new test of Lorentz invariance performed by comparing the resonance frequencies of two orthogonal cryogenic optical resonators subject to Earths rotation over approximately 1 yr. For a possible anisotropy of the speed of light c, we obtain Delta(theta)c/c(0)=(2.6+/-1.7)x10(-15). Within the Robertson-Mansouri-Sexl (RMS) test theory, this implies an isotropy violation parameter beta-delta-1 / 2=(-2.2+/-1.5)x10(-9), about 3 times lower than the best previous result. Within the general extension of the standard model of particle physics, we extract limits on seven parameters at accuracies down to 10(-15), improving the best previous result by about 2 orders of magnitude.

Atom-Interferometry Tests of the Isotropy of Post-Newtonian Gravity

We present a test of the local Lorentz invariance of post-Newtonian gravity by monitoring Earths gravity with a Mach-Zehnder atom interferometer that features a resolution of up to 8 x 10{-9}g/sqrt[Hz], the highest reported thus far. Expressed within the standard model extension (SME) or Nordtvedts anisotropic universe model, the analysis limits four coefficients describing anisotropic gravity at the ppb level and three others, for the first time, at the 10 ppm level. Using the SME we explicitly demonstrate how the experiment actually compares the isotropy of gravity and electromagnetism.

Atom Interferometry with up to 24-Photon-Momentum-Transfer Beam Splitters

We present up to 24-photon Bragg diffraction as a beam splitter in light-pulse atom interferometers to achieve the largest splitting in momentum space so far. Relative to the 2-photon processes used in the most sensitive present interferometers, these large momentum transfer beam splitters increase the phase shift 12-fold for Mach-Zehnder (MZ) and 144-fold for Ramsey-Bordé (RB) geometries. We achieve a high visibility of the interference fringes (up to 52% for MZ or 36% for RB) and long pulse separation times that are possible only in atomic fountain setups. As the atoms internal state is not changed, important systematic effects can cancel.

Rotating optical cavity experiment testing Lorentz invariance at the 10-17 level

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 single block of fused silica and are rotated continuously on a precision air bearing turntable. An analysis of data recorded over the course of one year sets a limit on an anisotropy of the speed of light of

Tests of relativity by complementary rotating Michelson-Morley experiments.

\ensuremath{\Delta}c/c\ensuremath{\sim}1\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}17}

Test of the isotropy of the speed of light using a continuously rotating optical resonator.

. This constitutes the most accurate laboratory test of the isotropy of

The CSPAD megapixel x-ray camera at LCLS

c

Electromagnetic cavities and Lorentz invariance violation

to date and allows to constrain parameters of a Lorentz violating extension of the standard model of particle physics down to a level of

Atom interferometry tests of local Lorentz invariance in gravity and electrodynamics

{10}^{\ensuremath{-}17}

Atom interferometers with scalable enclosed area.

.