Creation of wormholes during the cosmological bounce

Abstract

In this work we demonstrate that wormholes can in principle be naturally created during the cosmological bounce without the need for the exotic matter or any kind of additional modifications of the gravitational sector, apart from the one enabling the cosmological bounce. This result is general and does not depend on the details of the modifications of gravitational equations needed to support the bounce. To study the possible existence of wormholes around the cosmological bounce we introduce general modifications of Einstein's field equations need to support the bouncing solutions. In this regime we show that it is possible to construct a cosmological wormhole solution supported by matter, radiation and vacuum energy, satisfying the Weak Energy Condition (WEC), which asymptotically approaches the Friedmann-Lemaître-Robertson-Walker (FLRW) metric. However, at a specific cosmological time, which depends on the parameters of the bouncing cosmological model, the WEC describing the matter needed to support such wormholes is spontaneously violated. This means that such wormholes could potentially exist in large numbers during some period around the bounce, significantly changing the causal structure of space-time, and then vanish afterwards.

Geodesically complete cyclic cosmologies and entropy

“…Starting from the early proposal of Tolman [3], there were many proposed models of cyclic universe, based on different specific assumptions and theoretical additions to general theory of relativity and standard cosmological model, specially in the last decades [4][5][6][7][8][9][10][11]. Recently, a general model-independent approach to study cyclic cosmologies was proposed in [2] and [1], and also applied to the problem of magnetogenea e-mail: petar.pavlovic@kozmologija.org b e-mail: marko.sossich@fer.hr (corresponding author) sis [12], cosmological constant problem [13] and creation of wormholes around the cosmological bounce [14].…”

Parity-violation in bouncing cosmology

“…One important issue is the ghost and gradient instabilities in the bouncing phase, which is a generic feature in a large class of theories [75][76][77]. To acquire a healthy bouncing model, new physics effective at bouncing phase is introduced [78][79][80][81][82][83][84][85][86][87][88][89][90][91][92][93][94][95].…”