The Time Machine Factory [unspeakable, speakable] on Time Travel - TMF2024

Warp Drives, Black Holes, and Wormholes

24 Sept 2024, 17:05

25m

Vallauri Hall (INRiM historical building, Turin)

talk Session IV. Faster than light, warp drive

Speaker

Kirill Zatrimaylov (Università degli Studi di Bergamo)

Description

As was shown by Ellis in gr-qc/0411096, one can establish a
correspondence between the Schwarzschild metric and a warp drive-type
metric, making it possible to consider a warp drive in a black hole
background. We elaborate upon this result and demonstrate that the
black hole's gravitational field can alleviate the violations of
energy conditions, reducing the amount of negative energy required to
sustain a warp bubble. Besides, we demonstrate that the black hole
horizon is effectively absent for the observers inside the bubble,
making it possible for them to send a light signal from the inside to
the outside.

We also generalize the Ellis scheme to the case of Morris-Thorne
wormholes and prove that Alcubierre warp drives cannot traverse
humanly traversable wormholes and can only pass through those that
either have a horizon or violate the flare-out condition. However,
this "no-go" theorem does not apply to another class of warp drive
solutions, the spherically symmetric warp drives, that are not
localized in space, and have the form of spherical waves.

Presentation materials

Zatrimaylov_talk.pdf