3 papers
gr-qc2024
From the Janis-Newman-Winicour naked singularities to Einstein-Maxwell phantom wormholes
Changjun Gao, Jianhui Qiu
The Janis-Newman-Winicour spacetime corresponds to a static spherically symmetric solution of Einstein equations with the energy momentum tensor of a massless quintessence field. I…
gr-qc2024
A small cosmological constant from a large number of extra dimensions
Changjun Gao
In this article, we consider the dimensional spacetimes among which one is the four dimensional physical Universe and the other is an n-dimensional sphere with constant radiu…
gr-qc2024
A novel two-field pure K-essence for inflation, dark matter, dark energy and black holes
Changjun Gao
K-essence theories are usually studied in the framework of one scalar field . Namely, the Lagrangian of K-essence is the function of scalar field and its covariant derivativ…