Suzanne Staggs is an experimentalist who makes measurements of the cosmic microwave background (CMB) radiation left over from the universal primeval plasma. (As the universe expanded and cooled, the photons eventually decoupled from the baryonic matter when their typical energies were insufficient to ionize hydrogen; at that point the universe became largely neutral and the photons passed through it without scattering.) The current experiments are of two types: measurements of the polarization of the CMB and of the CMB's very fine-scale features.
The experiments take advantage of the recent surge in innovative and sensitive detectors for microwave and millimeter radiation. The experimental CMB group includes Joe Fowler, Norman Jarosik, Bill Jones, and Lyman Page, as well as some dozen graduate students and several postdocs. We have close ties to the theoretical cosmologists in the department (Paul Steinhardt and Frans Pretorius), and we also collaborate with many members of the astrophysics department. Our experimental program is characterized by a nicely-balanced mix of very technical, cutting-edge hands-on work with detectors and optics, and design of experiments robust to the many subtle systematic effects possible in this work, combined with plenty of data analysis, using the many powerful statistical techniques now common to the field of CMB research.
The polarization of the CMB is only a few parts per billion. It arises from the fact that an unpolarized incident wave scattered from an electron emerges with an angle-dependent polarization; anisotropy in the radiation at the time of its last encounter with electrons results in a net polarization of the CMB. The majority of the polarization patterns emerge because of the anisotropy in the primordial plasma at the time of decoupling; this same anisotropy is probed exquisitely well by the present day maps of the CMB temperature by, for example, WMAP. However, gravity waves leftover from an epoch of inflation in the first few atto-attoseconds of the universe can also present anisotropic scattering conditions and thus imprint polarization onto the CMB; in distinction to the those from the plasma anisotropies, these patterns can come in either global parity. Therefore, detailed study of the polarization may provide information on the inflation potential itself! More information can be found in many places; one is a recent review article by Samtleben, Staggs & Winstein.
Measurement of the fine-scale features in the temperature of the CMB across the celestial sphere (at arcminute scales) probe the universe in new ways to the extant larger-angular-scale measurements. Those larger-angular-scale measurements, captured in the beautiful measurements from WMAP, paint a picture of the fundamental properties of our universe, including its baryon content, its dark matter content, its spatial geometry, and the fact that it is permeated with dark energy. Measurements at arcminute scales (fine scales) will provide further explanation of how the universe has evolved to its present day state, and will address questions about the nature of the dark energy itself.
Now that the CAPMAP polarization project is concluded (results), Staggs is involved in three major efforts. The first of these is the Atacama Cosmology Telescope project, also known as ACT. The first stages of the project are aimed at making large maps of the fine-scale features in the CMB. Our group is intimately involved at all levels of the project, but in particular, we are in charge of the detector array assemblies. The second major effort is the QUIET project aimed at measuring the polarization of the CMB at small and large angular scales. Our group has worked on the receiver effort by delivering the waveguide polarizers and some room-temperature electrical components, and is currently working on calibration methods. We also intend to support the fielding of the receivers. The third major effort is development of an as-yet-unnamed polarization experiment aimed at measuring-large-scale polarization using the power of large numbers of transition edge sensors (TES) detectors (as used for ACT) in novel configurations. We are interested in attracting new students on all these efforts.
- The Cosmic Microwave Background for Pedestrians: A Review for Particle and Nuclear Physicists, Samtleben, D., Staggs, S. T., & B. Winstein, 2007, ARNPS, 57, p.245-283 astro-ph/0803.0834
- New Measurements of Fine-Scale CMB Polarization Power Spectra from CAPMAP at Both 40 and 90 GHz. CAPMAP Collaboration: C. Bischoff, L. Hyatt, J. J. McMahon, G. W. Nixon, D. Samtleben, K. M. Smith, K. Vanderlinde, D. Barkats, P. Farese, T. Gaier, J. O. Gundersen, M. M. Hedman, S. T. Staggs, B. Winstein, 2008, submitted to APJ. astro-ph/0802.0888
- Optical Design of the Atacama Cosmology Telescope and the Millimeter Bolometric Array Camera, Fowler, J. W., Niemack, M. D., Dicker, S. R. , Aboobaker, A. M., Ade, P. A. R., Battistelli, E., Devlin, M. J., Fisher, R. P., Halpern, M., Hargrave, P. C., Hincks, A., Kaul, M., Klein, J., Lau, J., Limon, M., Marriage, T. A., Mauskopf, P. D., Page, L., Staggs, S. T., Swetz, D. N., Switzer, E., Thornton, R., & Tucker, C. E., 2007, Applied Optics IP, 46, pp.3444-3454. astro-ph/0701020
- Princeton Problems in Physics, with Solutions, Nathan Newbury, Michael Newman, John Ruhl, Suzanne Staggs, and Stephen Thorsett, 1990, Princeton University Press. (Monograph.)