Structure and stability of traversable thinshell wormholes in Palatini f (R ) gravity
Abstract
We study the structure and stability of traversable wormholes built as (spherically symmetric) thin shells in the context of Palatini f (R ) gravity. Using a suitable junction formalism for these theories we find that the effective number of degrees of freedom on the shell is reduced to a single one, which fixes the equation of state to be that of massless stressenergy fields, contrary to the general relativistic and metric f (R ) cases. Another major difference is that the surface energy density threading the thin shell, needed in order to sustain the wormhole, can take any sign and may even vanish, depending on the desired features of the corresponding solutions. We illustrate our results by constructing thinshell wormholes by surgically grafting Schwarzschild spacetimes and show that these configurations are always linearly unstable. However, surgically joined ReissnerNordström spacetimes allow for linearly stable, traversable thinshell wormholes supported by a positive energy density provided that the (squared) masstocharge ratio, given by y =Q^{2}/M^{2}, satisfies the constraint 1 <y <9 /8 (corresponding to overcharged ReissnerNordström configurations having a photon sphere) and lies in a region bounded by specific curves defined in terms of the (dimensionless) radius of the shell x_{0}=R /M .
 Publication:

Physical Review D
 Pub Date:
 November 2020
 DOI:
 10.1103/PhysRevD.102.104012
 arXiv:
 arXiv:2009.10997
 Bibcode:
 2020PhRvD.102j4012L
 Keywords:

 General Relativity and Quantum Cosmology
 EPrint:
 10 pages, revtex41 style. v2: some minor corrections, version accepted for publication in Phys. Rev. D