Speaker
Description
POLARBEAR is a ground-based CMB polarization experiment that is designed to characterize
the B-mode (curl component) signal at both degree and sub-degree angular-scales.
B-modes at degree scale can reveal the existence of primordial gravitational waves and will be
used for quantitative studies of inflation, such as the energy scale at which it occurred.
The sub-degree polarization data are an excellent tracer of the cosmological expansion rate
and large-scale structure in the universe through gravitational lensing, and can be used to constrain
the sum of the Neutrino masses.
POLARBEAR-1 started observing in early 2012 at 150 GHz with an array of 1,274
polarization-sensitive antenna-coupled transition-edge sensor (TES) bolometers,
and first detected the sub-degree B-mode signal using CMB data alone.
The POLARBEAR-2 is a project for receiver upgrade to cover two frequency bands
with 7,600 detectors per receiver
The Simons Array is a project to deploy three POLARBEAR-2 receivers on three telescopes.
Simons Array will survey of B-mode polarization at 95, 150, 220, and 270 GHz for
effective monitoring and removal of foreground contamination.
The first receiver is in final stage of integration.
It is scheduled to deploy during the 2017/2018 austral summer season in the Atacama desert in Chile.
The projected constraints on the tensor-to-scalar ratio (the amplitude of inflationary B-mode signal)
will improve over current constraints by almost an order
of magnitude to $\sigma(r=0.1) = 6.0\times10^{-3}$ ($4.0\times10^{-3}$ statistical), and the sensitivity to the sum of the neutrino masses
when combined with DESI spectroscopic galaxy survey data will be 40 meV at 1-sigma after foreground removal (19 meV(stat.)).
We will describe the current status and prospects of the POLARBEAR-2 receiver system
and the Simons Array project.
