Publications and Collaborations

Collaborations:

I’m a member of the QG-MM: COST Action CA18108. In particular I am a member of the committee for outreach and gender activities and the chair for the “Causality Based Theories” subchapter for the upcoming review.

The following of my Publications are personally my favorites:

Mark Bugden, and Claudio F. Paganini. “The Λ to zero limit of spacetimes and its physical interpretation.” Classical and Quantum Gravity (2019).

In this paper we show that one can consider a  hierarchy of validity for the Einstein equations in a de-Sitter universe similar to the situation in Quantum Mechanics with the Quantum-Classical correspondence. We use the Geroch notion of limits of spacetimes to make a heuristic argument (analogue to the quantum classical limit) for a domain of validity within which the Einstein equations provide a good approximation.
What makes this my favorite paper is however due to what I would consider my proudest academic achievement so far:

I now have a peer reviewed and published paper that has an inflatable boat in the acknowledgement.
“We would like to thank Hermine (Boat) for her essential support during the conceptional phase of this paper.”

Mars, Marc, Claudio F. Paganini, and Marius A. Oancea. The fingerprints of black holes—shadows and their degeneracies. Classical and Quantum Gravity 35, no. 2 (2017): 025005.

The cool thing about this paper is that the result is essentially counterintuitive. We showed that despite the fact that nothing escapes a black hole, an outside observer can nevertheless extract all the physical parameters of the black hole by analyzing its shadow.

Lars Andersson,  Siyuan Ma, Claudio F. Paganini, and Bernard F. Whiting. “Mode stability on the real axis.” Journal of Mathematical Physics 58, no. 7 (2017): 072501.

The interesting thing here is that for the approach to work we need to explore a delicate balance between the redshift at the event horizon and the blue shift at the Cauchy horizon. So far this seems to only work for the Teukolsky equation in Kerr. Other cases, that might seem intuitively similar, such as the charged scalar field on Reissner-Nordström do not satisfy this delicate balance.


Further Publications

Finster, F., & Paganini, C. F. (2020). “Incompatibility of Frequency Splitting and Spatial Localization: A Quantitative Analysis of Hegerfeldt’s Theorem”. arXiv preprint arXiv:2005.10120.

Paganini, C. F. (2020). “Nothing Happens on Closed Causal Curves”. arXiv preprint arXiv:2005.05748.

Finster, F., Fröhlich, J., Oppio, M. and Paganini, C.F., (2020). “Causal Fermion Systems and the ETH Approach to Quantum Theory.” arXiv preprint arXiv:2004.11785.

Oancea, M.A., Joudioux, J., Dodin, I.Y., Ruiz, D.E., Paganini, C.F. and Andersson, L., (2020).  “The gravitational spin Hall effect of light.” arXiv preprint arXiv:2003.04553.

Oancea, M. A., Paganini, C. F., Joudioux, J., & Andersson, L. (2019). “An overview of the gravitational spin Hall effect.” arXiv preprint arXiv:1904.09963.

Paganini, C.F., (2020). “Proposal 42: A New Storyline for the Universe Based on the Causal Fermion Systems Framework.”  In Progress and Visions in Quantum Theory in View of Gravity (pp. 119-154). Birkhäuser, Cham.

Claudio F. Paganini, and Marius A. Oancea, (2018). “Smoothness of the future and past trapped sets in Kerr–Newman–Taub-NUT spacetimes.” Classical and Quantum Gravity 35, no. 6 : 067001.


Lecture Notes

Claudio F. Paganini, Blazej Ruba, and Marius A. Oancea, (2016). “Characterization of Null Geodesics on Kerr Spacetimes.” arXiv preprint arXiv:1611.06927 .