Multi-horizon and Critical Behavior in Gravitational Collapse of Massless Scalar

TL;DR

This paper investigates the gravitational collapse of a massless scalar field, revealing multi-horizon formation and a new critical behavior with universal exponents during instant black hole expansion.

Contribution

It introduces the concept of multi-horizon formation and identifies a novel critical behavior during instant black hole expansion in scalar field collapse.

Findings

Multi-horizon formation occurs during collapse or accretion.

A new type of critical behavior is observed at instant expansion.

Critical exponents are found to be universal.

Abstract

This paper studies the whole process of gravitational collapse and accretion of a massless scalar field in asymptotically flat spacetime. Two kinds of initial configurations are considered. One is the initial data without black hole, the other contains a black hole. Under suitable initial conditions, we find that multi-horizon will appear, which means that the initial black hole formed by gravitational collapse or existing at the beginning will instantly expand and suddenly grow, rather than grows gradually in the accretion process. A new type of critical behavior is found around the instant expansion. The numerical computation shows that the critical exponents are universal.