Moonju Hong | Searcharxiv

arXiv2018

On non-Abelian T-duality for non-semisimple groups

We revisit non-Abelian T-duality for non-semisimple groups, where it is well-known that a mixed gravitational-gauge anomaly leads to $σ$-models that are scale, but not Weyl-invariant. Taking into account the variation of a non-local anomalous term in the T-dual $σ$-model of Elitzer, Giveon, Rabinovici, Schwimmer \& Veneziano, we show that the equations of motion of generalized supergravity follow from the $σ$-model once the Killing vector $I$ is identified with the trace of the structure constants. As a result, non-Abelian T-duals with respect to non-semisimple groups are solutions to generalized supergravity. We illustrate our findings with Bianchi spacetimes.

hep-th↗

arXiv2017

Motion of a Test Particle in the Reissner-Nordstrom Spacetime

This paper focuses on the motion of a test particle moving around the Reissner-Nordstrom black hole. It deals with circular motion and radial motion of the neutral massive test particles, and shortly handles circular motion of the charged massive test particles. Both neutral and charged particles are affected by black hole's charge, but it is due to the fact that charge of the black hole bends the spacetime more strongly. This procedure has nothing to do with electromagnetic interactions, and these are only considered for charged test particles. However, it only treats mathematically easy, approximated situations and general motions and complex motions will not be discussed. This paper has tried to get some physical information only with the easiest mathematical tools and without difficult concepts that general relativity contains. Contents of this paper would be suitable for those who want to know something about the Reissner-Nordstrom black hole, but does not have much knowledge in this field. They can begin their intellectual journey with this paper.

gr-qc↗