COSMIC MICROWAVE BACKGROUND POLARIZATION

Polarization of the cosmic microwave background, though not yet detect ed, provides a source of information about cosmological parameters com plementary to temperature fluctuations. This paper provides a complete theoretical treatment of polarization fluctuations. After a discussio n of the physics of polarization, the Boltzmann equation governing the evolution of the photon density matrix is derived from quantum theory and applied to microwave background fluctuations, resulting in a comp lete set of transport equations for the Stokes parameters from both sc alar and tensor metric perturbations. This approach is equivalent at l owest order in scattering kinematics to classical radiative transfer, and provides a general framework for treating the cosmological evoluti on of density matrices. The metric perturbations are treated in the ph ysically appealing longitudinal gauge. Expressions for various tempera ture and polarization correlation functions are derived. Detection pro spects and theoretical utility of microwave background polarization ar e briefly discussed. (C) 1996 Academic Press, Inc.