Our research group designs experiments and develops analytical methods to study the early Universe through observations of the Cosmic Microwave Background radiation (CMB). The existence of this extremely faint signal is a direct consequence of the expansionary evolution of the early Universe. The prediction and subsequent observational confirmation of this relic background represents one of the most important pillars of modern observational cosmology. Comparison of the statistical properties of the CMB with the predictions of parametric models has revolutionized our understanding of the basic physics that governs the large-scale properties of our Universe.
Despite the success of the currently accepted “Standard Model” of cosmology, our understanding of the early Universe is by no means complete. For example, the theory currently postulates that the very early Universe underwent a period of very rapid expansion, termed Inflation, which explains the observed isotropy, homogeneity, and geometry of the Universe, and provides the necessary conditions for the formation of galaxies and clusters of galaxies that we observe today. However, although the existence of an Inflationary period is backed by several lines of anecdotal evidence, to date there is no direct observational evidence that conclusively validates the theory.
Currently, our efforts are centered on two experiments:
The High-Frequency Instrument (HFI) aboard the Planck surveyor is an orbital mission designed to make maps of the CMB in six frequency bands between 100 GHz and about 1 THz. This data set will result in cosmic-variance-limited measurements of the CMB temperature anisotropies out to angular scales well into the Silk damping tail of the CMB. Planck HFI will also search for the Cosmic Gravitational Wave Background (CGWB) that would have resulted from a period of Inflation via its unique signature in the polarization of the CMB.
SPIDER is a balloon-borne experiment that is designed to complement the Planck HFI through lower-resolution but much more sensitive polarization observations. SPIDER will undertake two flights, taking advantage of the uniquely low backgrounds and benign systematic environment of the balloon platform to measure the CGWB on the largest angular scales. These observations will help lay the technical foundation for any future orbital mission dedicated to the characterization of this signal.
Research supported by the National Science Foundation, the National Aeronautics and Space Administration, the Gordon and Betty Moore Foundation, and the David and Lucile Packard Foundation