Vaidya spacetimes, black-bounces, and traversable wormholes ID ID 1 ID Alex Simpsony , Prado Mart´ın–Morunoz , and Matt Visser ySchool of Mathematics and Statistics, Victoria University of Wellington, PO Box 600, Wellington 6140, New Zealand zDepartamento de F´ısica Te´orica and IPARCOS, Universidad Complutense de Madrid, E-28040 Madrid, Spain E-mail:
[email protected],
[email protected];
[email protected] Abstract: We consider a non-static evolving version of the regular \black-bounce"/traversable wormhole geometry recently introduced in JCAP02(2019)042. We first re-write the static metric using Eddington{Finkelstein coordinates, and then allow the mass pa- rameter m to depend on the null time coordinate (`ala Vaidya). The spacetime metric is 2m(w) ds2 = 1 dw2 ( 2 dw dr) + r2 + a2 dθ2 + sin2 θ dφ2 : − − pr2 + a2 − ± Here w = u; v denotes suitably defined outgoing; ingoing null time coordinates; f g f g representing retarded; advanced time, while, (at least for a = 0), we allow r f g 6 2 ( ; + ). This spacetime is still simple enough to be tractable, and neatly inter- −∞ 1 polates between Vaidya spacetime, a black-bounce, and a traversable wormhole. We show how this metric can be used to describe several physical situations of particular interest, including a growing black-bounce, a wormhole to black-bounce transition, and the opposite black-bounce to wormhole transition. A arXiv:1902.04232v3 [gr-qc] 26 Jun 2019 Date: 12 February 2019; 25 June 2019; LTEX-ed June 27, 2019 Keywords: Vaidya spacetime; regular black hole; black-bounce; null-bounce; traversable wormhole.