Macroscopic noncommutative-geometry wormholes as emergent phenomena in $f(Q)$ gravity

Abstract

Noncommutative geometry, an offshoot of string theory, replaces point-like particles by smeared objects. These local effects have led to wormhole solutions in a semiclassical setting, but it has also been claimed that the noncommutative effects can be implemented by modifying only the energy momentum tensor in the Einstein field equations, while leaving the Einstein tensor unchanged. The implication is that noncommutative-geometry wormholes could be macroscopic. This result can be readily explained by considering the noncommutative-geometry background to be a fundamental property and the macroscopic wormhole spacetime to be emergent, according to an earlier version of this paper. However, it is shown in the present version that such wormholes could not be sufficiently massive to exist on a macroscopic scale. A major objective in this paper is to invoke $f(Q)$ gravity to provide the extra degrees of freedom to overcome these obstacles.