A new time-machine model with compact vacuum core

TL;DR

This paper introduces a novel vacuum spacetime solution that develops closed timelike curves, enabling a time-machine model with a causality-violating core that satisfies key energy conditions and remains regular and asymptotically flat.

Contribution

It presents a new class of vacuum solutions leading to a time-machine model with a causality-violating core that adheres to physical energy conditions.

Findings

Causality violation occurs inside an empty torus.

The matter field satisfies all standard energy conditions.

The model is regular and asymptotically flat.

Abstract

We present a class of curved-spacetime vacuum solutions which develope closed timelike curves at some particular moment. We then use these vacuum solutions to construct a time-machine model. The causality violation occurs inside an empty torus, which constitutes the time-machine core. The matter field surrounding this empty torus satisfies the weak, dominant, and strong energy conditions. The model is regular, asymptotically-flat, and topologically-trivial. Stability remains the main open question.