Bridging inflation and reheating: chiral gravitational waves from aHz to GHz
by
Chao Chen
→
Asia/Seoul
447-1 (IBS CTPU-CGA)
447-1
IBS CTPU-CGA
Description
In this paper, we investigate chiral gravitational wave (GW) signals generated from inflation to reheating, driven by a parity-violating (PV) term coupled to the inflaton. During inflation, the PV term reduces the sound horizon for right-handed circularly polarized GWs, and amplifies their power spectra relative to left-handed GWs. At CMB scales, these chiral GWs induce BB as well as nonvanishing EB and TB correlations in CMB, which are potentially detectable by LiteBIRD. During reheating, subhorizon modes undergo tachyonic instability, leading to fully circularly polarized GWs with enhanced amplitudes, detectable through the resonant cavity experiment. The absence of backreaction effect of enhanced chiral GWs imposes constraints on the energy scale of the PV term, the inflationary potential, and the reheating history. Our findings highlight the potential of multi-frequency GW experiments to offer a unique probe of the parity violation and early Universe.
Bio: Chao Chen received his PhD from the University of Science and Technology of China in 2021. Later that year, he joined the Jockey Club Institute for Advanced Study at the Hong Kong University of Science and Technology as a postdoctoral researcher. In October 2024, he joined Jiangsu University of Science and Technology as a faculty member. His research interests focus on inflationary cosmology, gravitational waves, and primordial black holes. He is also working on the simulation of wave dark matter.