München 2009 – scientific programme

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GR: Fachverband Gravitation und Relativitätstheorie

GR 14: Experimente zur Gravitation I

GR 14.4: Talk

Thursday, March 12, 2009, 18:25–18:45, A214

Long-term test of the isotropy of the speed of light using an optical-resonator-based apparatus — Christian Eisele, Alexander Yu. Nevsky, and •Stephan Schiller — Institut für Experimentalphysik, Heinrich-Heine-Universität, 40225 Düsseldorf

The isotropy of the speed of light is one of the best known invariance principles in physics. It is one aspect of Lorentz Invariance, which is a basic assumption of all theories of the fundamental forces. In the course of the past 120 years the isotropy has been tested with ever increasing precision.

We have developed a highly sensitive laser Michelson-Morley apparatus [1] and performed an extensive search for violation of the isotropy of c. The apparatus contains two orthogonal optical high-finesse resonators (F=180 000) to which two waves obtained from a monolithic 1064 nm Nd:YAG laser are frequency-stabilised. The resonators are embedded in a monolithic structure made of ultra low thermal expansion coefficient glass (ULE). The apparatus is continuously rotated using a highly accurate air bearing rotation table. The difference frequency between the resonators is measured as a function of the orientation in space. The apparatus is also actively stabilized from mechanical vibrations, tilt variations and temperature fluctuations.

We will report about the results of a measurement campaign of approximately one year duration. From the data we obtain coefficients describing a possible violation of Lorentz Invariance within two test theories, the standard model extension (SME) and the Mansouri-Sexl test theory. [1] Eisele et al., Opt. Comm. 281, 1189 (2008)