Description
General relativity and cosmology have had a generous influx of ideas from science-fiction, with Matt contributing and influencing these developments significantly. The metric reverse-engineering that is at the core of this, is frequently called into question on diverse grounds—some better, some less so. Warp drives in particular have seen a recent resurgence with substantial controversy. In this talk, I will explain why reverse-engineering is a fine, time-honoured tradition beyond general relativity; why point-wise energy conditions are middling, at best; and why the the fate of these speculative metrics needs to be decided by the (so-far) equally speculative field of quantum gravity. After a summary of recent work on warp drives and their extensions, I will give an example of what sort of problem quantum gravity would have to solve in such contexts: Time travel through the lens of relational quantum dynamics. I will wrap up with some ideas on how to extent these first toy models to unwieldy physics besides time travel.