Traversable wormholes in General Relativity without exotic matter. (arXiv:2106.05034v3 [gr-qc] UPDATED)
<a href="http://arxiv.org/find/gr-qc/1/au:+Konoplya_R/0/1/0/all/0/1">R. A. Konoplya</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Zhidenko_A/0/1/0/all/0/1">A. Zhidenko</a>

In [J. Blazquez-Salcedo, C. Knoll, E. Radu, Phys. Rev. Lett. 126 (2021)
no.10, 101102] asymptotically flat traversable wormhole solutions were obtained
in the Einstein-Dirac-Maxwell theory without using exotic matter. The
normalizable numerical solutions found in [1] require a peculiar behavior at
the throat: the mirror symmetry relatively the throat leads to the
nonsmoothness of gravitational and matter fields. In particular, one must
postulate the changing of the sign of the fermionic charge density at the
throat requiring coexistence of particle and antiparticles without annihilation
and posing a membrane of matter at the throat with specific properties.
Apparently this kind of configurations could not exist in nature. We show that
there are wormhole solutions, which are asymmetric relatively the throat and
endowed by smooth gravitational and matter fields, being, thereby, free from
all the above problems. This indicates that such wormhole configurations could
also be supported in a realistic scenario.

In [J. Blazquez-Salcedo, C. Knoll, E. Radu, Phys. Rev. Lett. 126 (2021)
no.10, 101102] asymptotically flat traversable wormhole solutions were obtained
in the Einstein-Dirac-Maxwell theory without using exotic matter. The
normalizable numerical solutions found in [1] require a peculiar behavior at
the throat: the mirror symmetry relatively the throat leads to the
nonsmoothness of gravitational and matter fields. In particular, one must
postulate the changing of the sign of the fermionic charge density at the
throat requiring coexistence of particle and antiparticles without annihilation
and posing a membrane of matter at the throat with specific properties.
Apparently this kind of configurations could not exist in nature. We show that
there are wormhole solutions, which are asymmetric relatively the throat and
endowed by smooth gravitational and matter fields, being, thereby, free from
all the above problems. This indicates that such wormhole configurations could
also be supported in a realistic scenario.

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