Special Physics Colloquium - A Tale of Two B's: Searching for Signatures of Inflation

Event Date: 

Tuesday, September 23, 2014 - 4:00pm

Event Location: 

  • Broida 1640

Speaker:

Phil Lubin, UCSB

Abstract:

One consequence of many inflationary models is the production of gravitational waves. These gravitational wave are beyond our current abilities to directly detect but we may be able to detect them indirectly via there coupling to the photons that arise later from gravitational wave interaction with the plasma during ionized phases that then interacts via Thomson scattering with the Cosmic Microwave Background (CMB). Due to the topological nature of gravitational waves we expect a particular pattern of this effect on the linear polarization state of the CMB in the form of vorticy like terms (a Curl like component) analogous to the structure of magnetic fields and hence the term B modes. Unfortunately, the many of models of inflation lack predictive power as to the magnitude of the gravitational waves generated and hence we are left to search for phenomenon which may or may not be detectable with current or foreseeable technology. Searches are underway to try to observe or limit this effect. Recent observations by the BiCEP team have claimed detection of cosmological B modes in the CMB at a level that is both puzzling and becoming extremely controversial. In this talk I will review the overall issues related to searching for inflation, the details of the BiCEP claim and the possibility that their detection may not be that of inflation and the status of the CMB sky as measured by the ESA/ NASA Planck mission and discuss the highly complex nature of the many foregrounds that must be understood to properly search for inflationary signatures, including B modes.