Torsion-induced gravitational $\theta$ term and gravitoelectromagnetism
| Autor: | Chatzistavrakidis, Athanasios, Karagiannis, Georgios, Schupp, Peter |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Eur. Phys. J. C, 80 11 (2020) 1034 |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1140/epjc/s10052-020-08600-9 |
| Popis: | Motivated by the analogy between a weak field expansion of general relativity and Maxwell's laws of electrodynamics, we explore physical consequences of a parity violating $\theta$ term in gravitoelectromagnetism. This is distinct from the common gravitational $\theta$ term formed as a square of the Riemann tensor. Instead it appears as a product of the gravitoelectric and gravitomagnetic fields in the Lagrangian, similar to the Maxwellian $\theta$ term. We show that this sector can arise from a quadratic torsion term in nonlinear gravity. In analogy to the physics of topological insulators, the torsion-induced $\theta$ parameter can lead to excess mass density at the interface of regions where $\theta$ varies and consequently it generates a correction to Newton's law of gravity. We discuss also an analogue of the Witten effect for gravitational dyons. Comment: 5 pages, two-column format, v2: references added; minor corrections; revised journal version |
| Databáze: | arXiv |
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