Kinks, energy conditions and closed timelike curves

TL;DR

This paper explores the relationship between energy conditions, geodesic completeness, and closed timelike curves in cylindrically symmetric kinked spacetimes, revealing limitations on energy conditions and implications for causality violations.

Contribution

It establishes that neither strong nor weak energy conditions can be fully satisfied in such spacetimes and analyzes how quantum matter interacts with closed timelike curves.

Findings

Weak energy condition may hold on transversal sections.

Quantum matter can be trapped by closed timelike curves.

Causality violations are unobservable due to incoherent radiation.

Abstract

A link between the possibility of extending a geodessically incomplete kinked spacetime to a spacetime which is geodesically complete and the energy conditions is discussed for the case of a cylindrically-symmetric spacetime kink. It is concluded that neither the strong nor the weak energy condition can be satisfied in the four-dimensional example, though the latter condition may survive on the transversal sections of such a spacetime. It is also shown that the matter which propagates quantum-mechanically in a kinked spacetime can always be trapped by closed timelike curves, but signaling connections between that matter and any possible observer can only be made of totally incoherent radiation, so preventing observation of causality violation.