Casimir wormholes in modified symmetric teleparallel gravity

Hassan, Zinnat; Ghosh, Sayantan; Sahoo, P. K.; Bamba, Kazuharu

doi:10.1140/epjc/s10052-022-11107-0

Cited by 58 publications

(12 citation statements)

References 72 publications

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“…The associated Casimir energy has long been known to be a potential candidate source to generate and support a traversable WH (see e.g. [369,1517], as well as [1518][1519][1520][1521][1522][1523][1524][1525][1526][1527] for later works). In [1528], Garattini explicitly constructed various interesting traversable WH solutions supported by Casimir energy.…”

Section: Vector-tensor Horndeski Gravitymentioning

confidence: 99%

Horizon-scale tests of gravity theories and fundamental physics from the Event Horizon Telescope image of Sagittarius A ∗

Vagnozzi

Roy

Tsai

et al. 2023

Class. Quantum Grav.

290

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Horizon-scale images of black holes (BHs) and their shadows have opened an unprecedented window onto tests of gravity and fundamental physics in the strong-field regime. We consider a wide range of well-motivated deviations from classical General Relativity (GR) BH solutions, and constrain them using the Event Horizon Telescope (EHT) observations of Sagittarius A* (Sgr A*), connecting the size of the bright ring of emission to that of the underlying BH shadow and exploiting high-precision measurements of Sgr A*’s mass-to-distance ratio. The scenarios we consider, and whose fundamental parameters we constrain, include various regular BHs, string-inspired space-times, violations of the no-hair theorem driven by additional fields, alternative theories of gravity, novel fundamental physics frameworks, and BH mimickers including well-motivated wormhole and naked singularity space-times. We demonstrate that the EHT image of Sgr A* places particularly stringent constraints on models predicting a shadow size larger than that of a Schwarzschild BH of a given mass, with the resulting limits in some cases surpassing cosmological ones. Our results are among the first tests of fundamental physics from the shadow of Sgr A* and, while the latter appears to be in excellent agreement with the predictions of GR, we have shown that a number of well-motivated alternative scenarios, including BH mimickers, are far from being ruled out at present.

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Section: Vector-tensor Horndeski Gravitymentioning

confidence: 99%

Horizon-scale tests of gravity theories and fundamental physics from the Event Horizon Telescope image of Sagittarius A ∗

Vagnozzi

Roy

Tsai

et al. 2023

Class. Quantum Grav.

290

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“…The respective classes of connections are different from that used in [37] and whether such connections can pass the energy conservation criterion, is a future research question. Model-specific wormhole (WH) solutions were discussed in f (Q) theory [54,55], however further research on this topic is still needed. Banerjee et al [54] mentioned the non-existence of WH for quadratic f (Q) model, but no further attempt on investigating the actual reason of this discrepancy was done.…”

Section: Discussionmentioning

confidence: 99%

On the viability of f(Q) gravity models

Loo

2023

Class. Quantum Grav.

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In general relativity, the contracted Bianchi identity makes the field equation compatible with the energy conservation, likewise in $f(R)$ theories of gravity. We show that this classical phenomenon is not guaranteed in the symmetric teleparallel theory, and rather generally $f(Q)$ model specific. We further prove that the energy conservation criterion is equivalent to the affine connection's field equation of $f(Q)$ theory, and except the $f(Q)=\alpha Q+\beta$ model, the non-linear $f(Q)$ models do not satisfy the energy conservation or, equivalently the second field equation in every spacetime geometry; unless $Q$ itself is a constant. So the problem is deep-rooted in the theory, several physically motivated examples are provided in the support.

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“…The observational study of gravity was performed in [39−43]. Moreover, in the field of astrophysical objects, interesting literature can be found, for instance, on BHs [44,45], WH geometries [46−49], gavastars [50], spherically symmetric configurations [51], and quintessence fields [52] in gravity.…”

Section: Introductionmentioning

confidence: 99%

Non-exotic static spherically symmetric thin-shell wormhole solution in f (Q, T ) gravity*

2023

Self Cite

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In this study, we have conducted an analysis of traversable wormhole solutions within the framework of linear $f(Q, T) = \alpha Q + \beta T$ gravity, ensuring that all the energy cnditions hold for the entire spacetime. The solutions presented in this study were derived through a comprehensive analytical examination of the parameter space associated with the wormhole model. This involved considering the exponents governing the redshift and shape functions, as well as the radius of the wormhole throat ($r_0$), the redshift function value at the throat ($\phi_0$), and the model parameters ($\alpha$ and $\beta$). Also, we have established bounds on these free parameters that guarantee the satisfaction of the energy conditions throughout spacetime and have also provided two solutions. Further, we have used the Israel junction condition to see the stability of a thin-shell around the wormhole. We have also calculated the NEC criteria and potential for such a thin-shell and how it varies with the chosen shape function.

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Casimir wormholes in modified symmetric teleparallel gravity

Cited by 58 publications

References 72 publications

Horizon-scale tests of gravity theories and fundamental physics from the Event Horizon Telescope image of Sagittarius A ∗

Horizon-scale tests of gravity theories and fundamental physics from the Event Horizon Telescope image of Sagittarius A ∗

On the viability of f(Q) gravity models

Non-exotic static spherically symmetric thin-shell wormhole solution in f (Q, T ) gravity*

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