Jeff McMahon joins the Physics Department as an Assistant Professor in experimental cosmology. His focus includes constraining inflation and dark energy with cosmic microwave background studies. Measurements of the Cosmic Microwave Background (CMB) provide opportunities to pursue research topics at the forefront of both fields. Unexplored signals in the CMB have the potential to provide information about inflation (a GUT-scale phenomenon), potential for detection of gravitational waves, measurement of neutrino mass, and constraints on the properties of dark energy.

With the South Pole Telescope (SPT) collaboration, Professor McMahon helped build a 10-m telescope at the geographic South Pole. Outfitted with a powerful three-frequency camera, this instrument is currently surveying the CMB sky with unprecedented resolution and sensitivity. The data collected will be used to constrain dark energy through clusters detected with the Sunyaev-Zel’dovich effect, and to extend measurements of the CMB power spectrum to smaller angular scales. The sky maps that are being generated will be a powerful tool for cosmology and astrophysics for years to come.

Professor McMahon is also working on the development of SPTpol, which is the second SPT key project. This will consist of a polarization-sensitive camera to be deployed on the South Pole Telescope in 2011. The SPTpol data will constrain neutrino mass and the energy scale of inflation. Through his work on SPTpol, he has become involved in the development of new detectors for CMB polarization. In the coming years, these detectors will be used in a number of new experiments, which will dramatically improve the constraints on the energy scale of inflation.