Detecting Relic Gravitational Waves in the CMB: Comparison of Planck and Ground-based Experiments

Understand

We compare the detection abilities for the relic gravitational waves by two kinds of forthcoming cosmic microwave background radiation (CMB) experiments, space-based Planck satellite and the various ground-based experiments.

• Comparing with the ground-based experiments, Planck satellite can observe all the CMB power spectra in all the multipole range, but having much larger instrumental noises.
• We find that, for the uncertainty of the tensor-to-scalar ratio $\Delta r$, PolarBear (II) as a typical ground-based experiment can give much smaller value than Planck satellite.
• However, for the uncertainty of the spectral index $\Delta n_t$, Planck can give the similar result with PolarBear (II).