PhD Defenses


Mon September 27th 2021, 3:30pm

Ph.D. Candidate:  Hung-I (Eric) Yang

Research Advisor:  Chao-Lin Kuo

Date: Monday, September 27, 2021
Time: 3:30pm PDT

Zoom Link:

Zoom Password: email mariaf67 [at]

Title: Constraining Primordial Gravitational Waves and Characterizing B-mode with the Keck Array and BICEP3 CMB experiments

Cosmic Inflation is currently our best theory of what occurred in the first instances of the Universe. One unique prediction from many inflationary models is a stochastic gravitational wave background which would leave a B-mode imprint on the CMB polarization. BICEP3 and Keck Array are small-aperture refracting telescopes at the South Pole designed specifically to target the degree-scale inflationary B-modes. 

In this talk, we present the progress of the BICEP/Keck Array telescopes on measuring the inflationary B-modes with an emphasis on systematics mitigation. We will introduce the framework to study the CMB line-of-sight distortion fields, which is used as a powerful diagnostic for characterizing the observed B-modes. The distinct signatures in the EB and TB correlations generated by the distortions are used to study the associated systematic effects and physical processes. We demonstrated that the BK18 data set has no detectable spurious B-mode from distortions and set competitive constraints on the cosmological effects including gravitational lensing, patchy reionization, and cosmic birefringence.