24–28 Aug 2026
Leiden University
Europe/Zurich timezone

Primordial Gravitational Waves from Scalar Backreaction in Axion-SU(2) Inflation

Not scheduled
20m
Gorlaeus gebouw (Leiden University)

Gorlaeus gebouw

Leiden University

Einsteinweg 55, 2333 CC Leiden
Talk Early Universe

Speaker

Dr Mattia Cielo (NORDITA)

Description

In this work, we perform the first numerical study of strong scalar backreaction in spectator chromo-natural inflation (SCNI) in the case where the spectator sector decays during inflation. The tachyonic instability in scalar fluctuations, activated as the system crosses the $m_Q = \sqrt{2}$ threshold, amplifies perturbations and may significantly alter the background dynamics. The strong scalar backreaction regime introduces an effective quartic term in the potential for the gauge field background that rapidly drives it to zero, accelerating the axion-gauge system decay. We describe the dynamics of such decay and derive the gravitational wave spectrum for a set of benchmark parameters. Interestingly, the signal may peak at interferometer scales and lie within LISA's projected sensitivity.

Other topic / keywords: Axion Inflation - SU(2)

Author

Dr Mattia Cielo (NORDITA)

Presentation materials

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