Dissipative Inflation via Scalar Production. (arXiv:2305.07695v1 [hep-th])
<a href="http://arxiv.org/find/hep-th/1/au:+Creminelli_P/0/1/0/all/0/1">Paolo Creminelli</a>, <a href="http://arxiv.org/find/hep-th/1/au:+Kumar_S/0/1/0/all/0/1">Soubhik Kumar</a>, <a href="http://arxiv.org/find/hep-th/1/au:+Salehian_B/0/1/0/all/0/1">Borna Salehian</a>, <a href="http://arxiv.org/find/hep-th/1/au:+Santoni_L/0/1/0/all/0/1">Luca Santoni</a>

We describe a new mechanism that gives rise to dissipation during cosmic
inflation. In the simplest implementation, the mechanism requires the presence
of a massive scalar field with a softly-broken global $U(1)$ symmetry, along
with the inflaton field. Particle production in this scenario takes place on
parametrically sub-horizon scales, at variance with the case of dissipation
into gauge fields. Consequently, the backreaction of the produced particles on
the inflationary dynamics can be treated in a textit{local} manner, allowing
us to compute their effects analytically. We determine the parametric
dependence of the power spectrum which deviates from the usual slow-roll
expression. Non-Gaussianities are always sizeable whenever perturbations are
generated by the noise induced by dissipation: $f_{rm NL}^{rm eq} gtrsim
{O}(10)$.

We describe a new mechanism that gives rise to dissipation during cosmic
inflation. In the simplest implementation, the mechanism requires the presence
of a massive scalar field with a softly-broken global $U(1)$ symmetry, along
with the inflaton field. Particle production in this scenario takes place on
parametrically sub-horizon scales, at variance with the case of dissipation
into gauge fields. Consequently, the backreaction of the produced particles on
the inflationary dynamics can be treated in a textit{local} manner, allowing
us to compute their effects analytically. We determine the parametric
dependence of the power spectrum which deviates from the usual slow-roll
expression. Non-Gaussianities are always sizeable whenever perturbations are
generated by the noise induced by dissipation: $f_{rm NL}^{rm eq} gtrsim
{O}(10)$.

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