High Energy Physics Theory
Wean Hall 7408
Education & Professional Experience
Ph.D.: Syracuse University (2012)
Laurea Specialistica: University of Trieste, Theoretical Physics (2006)
Laurea: University of Trieste, Physics (2003)
Assistant Professor, Carnegie Mellon University, 2018–
Postdoctoral Fellow: University of Pennsylvania, 2016–2018
Postdoctoral Research Scientist: Columbia University, 2012–2016
I am interested in a variety of problems involving physical systems that range in size from laboratory to cosmological scales. This has led me over time to work on a variety of interesting problems in cosmology, astrophysics and condensed matter. More specifically, using quantum field theory techniques I have drawn connections among seemingly different phenomena, ranging from inflation and dark matter in cosmology, to tides, superradiance and black holes in astrophysics, to collective excitations in solids, superfluids and (anti-)ferromagnets.
My work on condensed matter systems is aimed at extending standard results in relativistic quantum field theory to finite-density states, with particular emphasis on the dynamics of collective excitations. A few highlights of my work in this direction include the application of the coset construction to (super-)fluids and (super-)solids, and the derivation of a finite-density version of Goldstone's theorem. By placing the emphasis on how symmetries are realized by systems at finite density I also put forward a classification of condensed-matter systems and their Wess-Zumino terms.
In the context of gravitational physics, I have derived a novel EFT approach to slowly-spinning, relativistic objects coupled to gravity. This work provided the foundation for an EFT description of tidal dynamics and superradiance---a phenomenon which can be used to probe the existence of light axions. Most of my research in cosmology has focused on improving our understanding of primordial perturbations produced during inflation. More recently, I have worked on models of dark matter aimed at reproducing the radial acceleration relation observed in spiral galaxies. I have also developed an EFT to describe perturbations of black holes with scalar hair.
G. Goon and R. Penco, Universal Relation between Corrections to Entropy and Extremality, Phys. Rev. Lett. 124, 101103 (2020)
S. Garcia-Saenz, J. Kang, R. Penco, Gauged galileons, J. High Energ. Phys. 2019, 81 (2019)
Gabriele Franciolini et al., Stable wormholes in scalar-tensor theories, J. High Energ. Phys. 2019, 221 (2019)
Gabriele Franciolini et al., Effective field theory of black hole quasinormal modes in scalar-tensor theories, J. High Energ. Phys. 2019, 127 (2019)
M.C. González, R. Penco, M. Trodden, Radiation of scalar modes and the classical double copy, J. High Energ. Phys. 11, 065 (2018)
B. Famaey, J. Khoury, and R. Penco, Emergence of the mass discrepancy-acceleration relation from dark matter-baryon interactions, J. Cosmol. Astropart. Phys. 1803, 03 (2018)
M. Carrillo-González, R. Penco, and M. Trodden, The classical double copy in maximally symmetric spacetimes, J. High Energ. Phys. 04, 028 (2018)
A. Nicolis and R. Penco, Mutual Interactions of Phonons, Rotons, and Gravity, Phys. Rev. B 97, 134516 (2018)
A. Esposito, S. Garcia-Saenz, A. Nicolis, and R. Penco, Conformal solids and holography, J. High Energ. Phys. 12, 113 (2017)
S. Endlich and R. Penco, A Modern Approach to Superradiance, J. High Energ. Phys. 05, 052 (2017)
A. Esposito, S. Garcia-Saenz, and R. Penco, First sound in holographic super fluids at zero temperature, J. High Energ. Phys. 12, 136 (2016)
S. Endlich and R. Penco, Effective field theory approach to tidal dynamics of spinning astrophysical systems, Phys. Rev. D 93, 064021 (2016)