"Experimental Limits on Gravitational Waves in the MHz Frequency Range with the Fermilab Holometer"
Tuesday, 10 Mar. 2015, 13:00 - 14:00
Presenter: Robert Lanza; KICP, University of Chicago, USA
Host: M. Aspelmeyer
Where: Schrödingerroom, 4th floor, Boltzmanngasse 5, 1090 Wien
In this talk I will present the results of a search for gravitational waves in the 1-11MHz frequency range using dual power-recycled Michelson laser interferometers at Fermi National Accelerator Laboratory. An unprecedented level of sensitivity to gravitational waves in this frequency range has been achieved by cross-correlating the output fluctuations of two identical and co-located 40m long interferometers. This technique produces sensitivities better than two orders of magnitude below the quantum shot-noise limit, within integration times of less than 1 hour, resulting in sensitivity to length changes at the level of 10^-20 meters/sqrt Hz. 95% confidence level upper limits are placed on the strain amplitude of MHz frequency gravitational waves at the 10^-21 Hz^-1/2 level, constituting the best direct limits to date at these frequencies. For gravitational wave power distributed over this frequency range, a broadband upper limit of 2.4*10^-21 Hz^-1/2 at 95% confidence level is also obtained. This talk will discuss the detector technology, the major challenges in pushing the limits of the instrument's sensitivity, and the upper limit results for gravitational wave radiation in the MHz band.