High-Speed Cylindrical Collapse of Perfect Fluid

TL;DR

This paper investigates the high-speed gravitational collapse of cylindrically symmetric perfect fluids, revealing conditions under which collapse halts or leads to singularity formation, with implications for realistic gases and tidal forces.

Contribution

It introduces a high-speed approximation scheme to analyze cylindrical perfect fluid collapse and identifies conditions affecting collapse outcomes and singularity formation.

Findings

High pressure relative to energy density halts collapse.

Large initial velocities can produce significant tidal forces.

Soft equations of state are necessary for singularity formation.

Abstract

The gravitational collapse of cylindrically distributed perfect fluid is studied. We assume the collapsing speed of fluid is very large and investigate such a situation by recently proposed high-speed approximation scheme. We show that if the value of the pressure divided by the energy density is bounded below by some positive value, the high-speed collapse is necessarily halted. This suggests that the collapsing perfect fluid of realistic ideal gas experiences the pressure bounce. However even in the case of mono-atomic ideal gas, arbitrarily large tidal force for freely falling observers are realizable by setting the initial collapsing velocity exceedingly large. In order that the high-speed collapse of cylindrical perfect fluid forms spacetime singularity, the equation of state should be very soft.