SPACE seminar: Rome Samanta — "Cosmic Defects as Windows to New Physics"

Tuesday 17 Mar 2026, 12:00 → 13:00 Europe/Rome

Aula 4 (San Marcellino)

Speaker: Rome Samanta (SSM)

Abstract:  I will begin with a brief overview of topological defects, such as domain walls and cosmic strings, and their connection to the stochastic gravitational-wave background. I will review current developments in the literature and highlight the main theoretical and phenomenological directions being explored. I will then focus on two key aspects of these defects. First, I will discuss how topological-defect physics can be used as a probe of previously unexplored regimes in particle-physics models. Second, I will introduce a non-standard class of defects that we are currently developing and discuss their potential implications for pulsar timing array observations.

References:

1. W.T. Emond, S. Ramazanov and R. Samanta, "Gravitational waves from melting cosmic strings," JCAP 01, 057 (2022) [arXiv:2108.05377 [hep-ph]].
2. E. Babichev, D. Gorbunov, S. Ramazanov, R. Samanta and A. Vikman, "NANOGrav spectral index $\gamma=3$ from melting domain walls," Phys. Rev. D 108, 123529 (2023)
   [arXiv:2307.04582 [hep-ph]].
3. M. Chianese, S. Datta, G. Miele, R. Samanta and N. Saviano,
   "Probing flavored regimes of leptogenesis with gravitational waves from cosmic strings," Phys. Rev. D 111, L041305 (2025) [arXiv:2406.01231 [hep-ph]]. 
4. M. Chianese, G. Domènech, T. Papanikolaou, R. Samanta and N. Saviano, "Induced Gravitational Waves as Cosmic Tracers of Leptogenesis," [arXiv:2504.20135 [hep-ph]].

 

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