Closed timelike curves and energy conditions in regular spacetimes

The authors investigate how violations of energy conditions relate to the presence of closed timelike curves in Kerr–Newman-type spacetimes. They introduce a correlation index that quantifies the overlap between CTC regions and energy-condition violations, and apply it to a regular noncommutative Kerr–Newman model to probe the local content of Hawking’s chronology protection conjecture. The results map out when (and how) energy-condition violations may help remove CTCs.

Eur. Phys. J. C 82, 1136 (2022)