NonGaussian microwave background fluctuations from nonlinear gravitational effects
Abstract
Whether the statistics of primordial fluctuations for structure formation are Gaussian or otherwise may be determined if the Cosmic Background Explorer (COBE) Satellite makes a detection of the cosmic microwavebackground temperature anisotropy delta T_{CMB}/T_{CMB}. NonGaussian fluctuations may be generated in the chaotic inflationary model if two scalar fields interact nonlinearly with gravity. Theoretical contour maps are calculated for the resulting SachsWolfe temperature fluctuations at large angular scales (greater than 3 degrees). In the longwavelength approximation, one can confidently determine the nonlinear evolution of quantum noise with gravity during the inflationary epoch because: (1) different spatial points are no longer in causal contact; and (2) quantum gravity corrections are typically small it is sufficient to model the system using classical random fields. If the potential for two scalar fields V(phi_{1,} phi_{2)} possesses a sharp feature, then nonGaussian fluctuations may arise. An explicit model is given where cold spots in delta T_{CMB}/T_{CMB} maps are suppressed as compared to the Gaussian case. The fluctuations are essentially scaleinvariant.
 Publication:

NASA STI/Recon Technical Report N
 Pub Date:
 June 1991
 Bibcode:
 1991STIN...9131067S
 Keywords:

 Anisotropy;
 Background Radiation;
 Gravitation Theory;
 Microwaves;
 Nonlinearity;
 Quantum Theory;
 Statistical Analysis;
 Temperature Effects;
 Astronomical Models;
 Cosmic Background Explorer Satellite;
 Gravitational Effects;
 Mathematical Models;
 Potential Fields;
 Random Processes;
 Relief Maps;
 Scalars;
 Temperature Distribution;
 Space Radiation