Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Traversable Wormholes in General Relativity   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 phantom matter. The
normalizable numerical solutions found therein 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 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 configuration could not exist in nature. We show that there are
wormhole solutions, which are asymmetric relative the throat and endowed by
smooth gravitational and matter fields, thereby being free from all the above
problems. This indicates that such wormhole configurations could also be
supported in a realistic scenario.

20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
25
The categories of this paper are: patt-sol
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
17
The categories of this paper are: q-fin
19
The categories of this paper are: eess
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg