This was the second scholarly paper i saw this year about time travel. Posting because there isn’t nearly enough serious interest about Time Travel in the science community.

Traversable acausal retrograde domains in spacetime.
Benjamin K Tippett1 and David Tsang2
Published 31 March 2017 •

Abstract
In this paper we present geometry which has been designed to fit a layperson’s description of a ‘time machine’. It is a box which allows those within it to travel backwards and forwards through time and space, as interpreted by an external observer. Timelike observers travel within the interior of a ‘bubble’ of geometry which moves along a circular, acausal trajectory through spacetime. If certain timelike observers inside the bubble maintain a persistent acceleration, their worldlines will close.