5 papers
Hidden-sector accretion and warped black-string seeds for high-redshift supermassive black holes
Chunshan Lin
The earliest massive black holes are often discussed in terms of heavy baryonic seeds, primordial black holes, or super-Eddington accretion. We develop a different possibility: a c…
Bypassing the Lyth Bound with Entangled Gravitons: Primordial Signatures and Late-Time Noise
Shingo Akama, Chunshan Lin
We demonstrate that quantum entanglement between primordial gravitons in dynamically decoupled gravitational sectors can parametrically enhance the tensor power spectrum during inf…
Scalar-assisted magnetogenesis during the radiation-dominated epoch
Alexander Ganz, Chunshan Lin, Mian Zhu
We propose a novel mechanism to generate primordial magnetic fields (PMFs) strong enough to explain the observed cosmic magnetic fields. We employ a scalar field charged under U(1)…
Constraining the Gravitational Wave Speed in the Early Universe via Gravitational Cherenkov Radiation
Paola C. M. Delgado, Alexander Ganz, Chunshan Lin +1
Scalar particles traveling faster than a subluminal gravitational wave generate gravitons via gravitational Cherenkov radiation. In this paper, we investigate graviton production b…
Parametric resonance of gravitational waves in general scalar-tensor theories
Yi-Fu Cai, Guillem Domènech, Alexander Ganz +3
Gravitational waves offer a potent mean to test the underlying theory of gravity. In general theories of gravity, such as scalar-tensor theories, one expects modifications in the f…