Duke Physics Colloquium: Inflationary Gravitational Radiation and Microwave Background Polarization

Duke Physics Colloquium
Arthur Kosowsky (University of Pittsburgh)

We live in a universe whose properties are remarkably well described by a very early epoch of accelerating expansion, termed inflation. One generic prediction of inflation is a relic background of stochastic gravitational radiation. These tensor metric perturbations leave a distinctive imprint in the polarization of the microwave background. In March 2014, the BICEP experiment at the South Pole announced the detection of this signal for the first time, although subsequent analysis cast doubt on whether polarized emission from dust in the Milky Way galaxy might be contaminating the signal. I will review the current state of observations and give an overview of upcoming observational efforts which will definitively distinguish the cosmological and galactic signals. If the BICEP signal has a significant component due to inflation, this opens the door to the remarkable possibility of detecting the gravitational radiation background directly with a space-based laser interferometer. Such a measurement would provide a precision probe of physics at energy scales a trillion times higher than those at terrestrial accelerators. Faculty Host: Tom Mehen. Refreshments will be served before and after the event in Physics room 128.

Wednesday, October 29, 2014 - 3:30pm
Physics 128
Paul, Cristin