30 citations · 97 across the 11 of their papers we have counts for
11 papers
Scalar Gravitational Waves Can Be Generated Even Without Direct Coupling Between Dark Energy and Ordinary Matter
Li-Ying Chou, Yi-Zen Chu, Yen-Wei Liu
We point out, the scalar sector of gravitational perturbations may be excited by an isolated astrophysical system immersed in a universe whose accelerated expansion is not due to t…
Cherenkov Gravitational Radiation During the Radiation Era
Yi-Zen Chu, Yen-Wei Liu
Cherenkov radiation may occur whenever the source is moving faster than the waves it generates. In a radiation dominated universe, with equation-of-state , we have recentl…
Late time tails and nonlinear memories in asymptotically de Sitter spacetimes
Yi-Zen Chu, M. Afif Ismail, Yen-Wei Liu
We study the propagation of a massless scalar wave in de Sitter spacetime perturbed by an arbitrary central mass. By focusing on the late time limit, this probes the portion of the…
Gravitational Tensor and Acoustic Waves in A Radiation Dominated Universe: Weyl Curvature and Polarization Patterns
Yi-Zen Chu, Yen-Wei Liu
We provide evidence that gravitational radiation in a 4D radiation-dominated universe, with equation-of-state , consists of two components: helicity-2 gravitons and massless…
The Transverse-Traceless Spin-2 Gravitational Wave Cannot Be A Standalone Observable Because It Is Acausal
Yi-Zen Chu, Yen-Wei Liu
We show, through an explicit calculation of the relevant Green's functions, that the transverse-traceless (TT) portion of the gravitational perturbations of Minkowski spacetime and…
Ghosts in the self-accelerating DGP branch with Gauss-Bonnet effect
Yen-Wei Liu, Keisuke Izumi, Mariam Bouhmadi-Lopez +1
The Dvali-Gabadadze-Porrati brane-world model provides a possible approach to address the late-time cosmic acceleration. However, it has subsequently been pointed out that a ghost…
Tensor Perturbations from Brane-World Inflation with Curvature Effects
Mariam Bouhmadi-Lopez, Yen-Wei Liu, Keisuke Izumi +1
The brane-world scenario provides an intriguing possibility to explore the phenomenological cosmology implied by string/M theory. In this paper, we consider a modified Randall-Sund…
Tradeoff between Smoother and Sooner "Little Rip"
Mariam Bouhmadi-Lopez, Pisin Chen, Yen-Wei Liu
There exists dark energy models that predict the occurrence of "little rip". At the point of little rip the Hubble rate and its cosmic time derivative approach infinity, which is q…
Scalar perturbations from brane-world inflation with curvature effects
Mariam Bouhmadi-Lopez, Pisin Chen, Yen-Wei Liu
We consider a generalization of the Randall-Sundrum single brane-world scenario (RS2). More precisely, the generalization is described through curvature corrections, corresponding…
Constraints on single entity driven inflationary and radition eras
Mariam Bouhmadi-Lopez, Pisin Chen, Yen-Wei Liu
We present a model that attempts to fuse the inflationary era and the subsequent radiation dominated era under a unified framework so as to provide a smooth transition between the…
Cosmological Imprints of a Generalized Chaplygin Gas Model for the Early Universe
Mariam Bouhmadi-Lopez, Pisin Chen, Yen-Wei Liu
We propose a phenomenological model for the early universe where there is a smooth transition between an early "quintessence" phase and a radiation dominated era. The matter conten…