Gravitational Wave Induced Large-scale Polarization of Cosmic Microwave Background Radiation

摘要

We discuss the contribution of gravitational wave to the cosmic microwavebackground radiation (CMBR) anisotropy and polarization. It is found that thelarge-scale polarization of CMBR is less than 1% for a standard recombinationuniverse. The effect of matter reionization will enhance the CMBR polarizationto a 10% level. We have computed the CMBR polarization for two extreme cases(not absolutely ruled out) and found that further enhancement of the ratio ispossible. We conclude that measuring the polarization of CMBR on large-angularscales can probe the ionization history of the early universe, set constraintson baryon density and the spectral index of the gravitational waves.