Chirality and Circular Polarization in Models of Inflation

Understand

We investigate the possibility that a chiral asymmetry during inflation can manifest as net circular polarization in photons.

• Using an example known to produce a helicity imbalance in fermions, we show that superhorizon photon modes produced during inflation acquire net circular polarization.
• Modes that reenter the horizon around last scattering can thermalize into the Cosmic Microwave Background while retaining a portion of their net circular polarization.
• We also consider the possibility of direct detection of the circular polarization in the CMB.