Measurement of the Cosmic Microwave Background Polarization Lensing
  Power Spectrum from Two Years of POLARBEAR Data
  We present a measurement of the gravitational lensing deflection power
spectrum reconstructed with two seasons cosmic microwave background
polarization data from the POLARBEAR experiment. Observations were taken at 150
GHz from 2012 to 2014 which survey three patches of sky totaling 30 square
degrees. We test the consistency of the lensing spectrum with a Cold Dark
Matter (CDM) cosmology and reject the no-lensing hypothesis at a confidence of
10.9 sigma including statistical and systematic uncertainties. We observe a
value of A_L = 1.33 +/- 0.32 (statistical) +/- 0.02 (systematic) +/- 0.07
(foreground) using all polarization lensing estimators, which corresponds to a
24% accurate measurement of the lensing amplitude. Compared to the analysis of
the first year data, we have improved the breadth of both the suite of null
tests and the error terms included in the estimation of systematic
contamination.
