## Team

### Julián Barragán Amado

##### team member

My name is **Julián Barragán Amado** and I am a Physicist.

In 2020, I obtained a double Ph.D. degree from the *University of Groningen* in the Netherlands and the Federal University of Pernambuco in Brazil, under the supervision of Prof. Elisabetta Pallante and Prof. Bruno Carneiro da Cunha, respectively.

During the PhD program, my research was focused on studying **linear perturbations of five-dimensional rotating black holes in anti-de Sitter**, also known as **Kerr-AdS5 black holes**. In this background, the equation of motion decouple into two second-order ordinary differential equations with four regular singular points. Using the method of **isomonodromic deformations**, I computed asymptotic expansions for the quasi-normal modes frequencies and the separation constant.

As a follow-up, I explored the low-temperature regime of these black holes as the confluent limit of the Heun equation and attempted a holographic interpretation of the unstable modes.

In 2021, I was a postdoctoral fellow in the Department of Mathematics of the *University of Sherbrooke* where I investigated the quasi-normal modes of scalar fields in the case of small Reissner-Nordström-AdS5 black holes at low temperatures.

In 2022, I joined the Gravity Group at *Dongguk University* as a Postdoc working on problems involving second-order ODEs with five regular singular points. Furthermore, I have been studying the connection coefficients of the (confluent) Heun equation expressed in terms of the Nekrasov-Shatashvili partition functions of SU(2) supersymmetric gauge theories with matter hypermultiplets.

### Selected publications

- J. Barragán Amado, B. Carneiro da Cunha, and E. Pallante, On the Kerr-AdS/CFT correspondence, JHEP 08 (2017) 094, arXiv:1702.01016.
- J. Barragán Amado, B. Carneiro da Cunha, and E. Pallante, Scalar quasinormal modes of Kerr-AdS$_{5}$, Phys. Rev. D 99 (2019), no. 10 105006, arXiv:1812.08921.
- J. Barragán Amado, B. Carneiro da Cunha, and E. Pallante, Vector perturbations of Kerr-AdS$_{5}$ and the Painlevé VI transcendent, JHEP 04 (2020) 155, arXiv:2002.06108.
- J. Barragán Amado, B. Carneiro da Cunha, and E.~Pallante, Remarks on holographic models of the Kerr-AdS$_{5}$ geometry, JHEP 05 (2021) 251, arXiv:2102.02657.
- J. Barragán Amado, B. C. da Cunha, and E. Pallante, Quasinormal modes of scalar fields on small Reissner-Nordström-AdS$_{5}$ black holes, Phys. Rev. D 105 (2022), no. 4 044028, arXiv:2110.08349.
- J. Barragán Amado, K. Kwon, and B. Gwak, Absorption cross section in gravity's rainbow from confluent Heun equation, Class. Quant. Grav. 41 (2024), no. 3 035005, arXiv:2307.12824.
- J. Barragán Amado and B. Gwak, Scalar quasi-normal modes of accelerating Kerr-Newman-AdS black holes, arXiv:2309.11355 (Accepted for publication in JHEP).