5 papers
Regularized big bang singularity: Geodesic congruences
Z. L. Wang
We investigate a particular regularization of big bang singularity, which remains within the domain of 4-dimensional general relativity but allowing for degenerate metrics. We stud…
Nonsingular bouncing cosmology from general relativity: Scalar metric perturbations
F. R. Klinkhamer, Z. L. Wang
We derive the equations of motion for scalar metric perturbations in a particular nonsingular bouncing cosmology, where the big bang singularity is replaced by a spacetime defect w…
Asymmetric nonsingular bounce from a dynamic scalar field
F. R. Klinkhamer, Z. L. Wang
We present a dynamical model for a time-asymmetric nonsingular bounce with a post-bounce change of the effective equation-of-state parameter. Specifically, we consider a scalar-fie…
Nonsingular bouncing cosmology from general relativity
F. R. Klinkhamer, Z. L. Wang
We investigate a particular type of classical nonsingular bouncing cosmology, which results from general relativity if we allow for degenerate metrics. The simplest model has a mat…
Lensing and imaging by a stealth defect of spacetime
F. R. Klinkhamer, Z. L. Wang
We obtain the geodesics for the simplest possible stealth defect which has a flat spacetime. We, then, discuss the lensing properties of such a defect, and the corresponding image…