Monday, September 22, 2008, Joint Physics Colloquium, 4:30 PM, 102 Thaw Hall, PITT

Tina Kahniashvili

Department of Physics, Kansas State University

"Gravitational Waves Astronomy as a Probe of the Early Universe"

Abstract:

Gravitational waves potentially represent our only direct probe of the Universe when it was less than one second old. I will briefly summarize the physical sources of relic gravitational waves, such as inflation, bubble collisions during phase transitions, primordial hydro- and MHD turbulence. I will present the inflationary gravitational waves signatures on CMB fluctuations. Using phenomenological parameters to describe phase transition properties, I will show the region of parameter space for which gravitational waves can be detected by the proposed Laser Interferometer Space Antenna (LISA). I will discuss gravitational waves polarization and show that if detected (through CMB or LISA), this will be an indication of parity and/or Lorentz symmetries breaking in the early Universe.