Studying the cosmological apparent horizon with quasistatic coordinates

摘要

This article aims at a natural generalization of the static coordinates to the (e?‘? + 1)-dimensional Friedmanna€“Lema??trea€“Robertsona€“Walker (FLRW) Universe. After demonstrating a no-go theorem, we put forward the quasistatic coordinates for the FLRW Universe. Then, the quasistatic coordinates are utilized to study the unified first law and the scalar-type perturbations on the cosmological apparent horizon.