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This theoretical study examines scalar perturbations in a two-scalar-field cosmological model that unifies warm inflation with dark matter and dark energy. The researchers derived and numerically solved perturbation equations using Fokker-Planck formalism, calculating the scalar spectral index and tensor-to-scalar ratio for different dissipation coefficient scalings. They found that scenarios with dissipation scaling as T^-1 are compatible with current cosmic microwave background observations, while the two-field model systematically produces larger spectral indices compared to standard single-field warm inflation.
Why it matters
This work advances theoretical frameworks attempting to unify early universe inflation with late-time cosmological phenomena like dark energy. If observationally validated, such unified models could simplify our understanding of cosmic evolution and reduce the number of independent components needed to explain cosmological observations.
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⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
Abstract: We investigate scalar perturbations in a two-scalar-field cosmological model unifying warm inflation, dark matter, and dark energy. The inflaton is noncanonically coupled to a second scalar field that acts as dark energy at late times. Assuming negligible dissipation and perturbations of the dark-energy field, we derive the linear scalar perturbations in a gauge-ready form, including quantum and thermal noise in the inflaton sector and stochastic fluctuations of the energy transfer to radiation. We numerically solve the coupled perturbation system using a Fokker-Planck formalism and compute the scalar spectral index $n_s$ and the tensor-to-scalar ratio $r$ for dissipation coefficients scaling as $T^p$ with $p=-1,, 1$ and $3$. For $p=-1$, we find scenarios compatible with current CMB observations in both the weak and strong dissipative regimes, while the explored scenarios with $p=1$ and $3$ are outside the observationally supported regions. Compared with standard single-field warm inflation, the two-scalar-field model yields a systematically larger spectral index for a given tensor-to-scalar ratio.
Source: Scalar perturbations in two-scalar-field warm inflation