Joint Seminar 14:30-16:00 Jonathan Ganc (UT Austin) Title: A new method for calculating the primordial bispectrum in the squeezed limit. Abstract: In 2003, Creminelli and Zaldarriaga proposed a consistency relation for the primordial curvature perturbation of all single-field inflation models; it related the bispectrum in the squeezed limit to the spectral tilt. Notably, their result is produced via classical arguments whereas most bispectrum calculations use quantum field theory (via the in-in formalism, for example). We have applied similar arguments to calculate the squeezed-limit primordial bispectrum using the in-in formalism and have arrived at a generic formula that doesn't rely on a slow-roll approximation. We were not able to verify the consistency relation in all generality, though it should be able to be demonstrated by our technique if it does, in fact, hold in general; we did explicitly verify it for slow-roll inflation (a known result) and for power-law inflation. Our technique could also be useful for calculating the single-field trispectrum in the squeezed limit and could be adapted for certain types of multi-field inflation models. 16:30-18:00 Norihiro Tanahashi (YITP, Kyoto) Title: Extradimension detection by gravitational wave observations Abstract: |

Last-modified: 2013-11-20 (水) 11:11:56 (2530d)