6 papers
Multifield stochastic inflation: Relevance of number of fields in statistical moments
Tomo Takahashi, Koki Tokeshi
In multifield inflation driven by scalar fields, symmetry renders the number of fields irrelevant at classical level. This ceases to be the case once stochastic effects…
An Effective Theory for Biased Tracers via the Boltzmann-Equation Approach
Tomohiro Fujita, Tomo Takahashi, Sora Yamashita
We develop an effective theory for biased tracers formulated at the level of the Boltzmann equation, providing a unified description of density and velocity bias. We introduce a ge…
Quantum state of interacting primordial inhomogeneities: de-squeezing and decoherence
Amaury Micheli, Yuto Oshima, Tomo Takahashi
We investigate how interactions affect the quantum state of scalar perturbations during inflation and the quantum correlations they may exhibit. Focusing on the case of scalar pert…
Reviving sub-keV warm dark matter: a UVLF-based analysis
Raymond T. Co, Siu Cheung Lam, Sai Chaitanya Tadepalli +1
Thermal warm dark matter (WDM) particles with are ruled out at more than by multiple observational probes, owing to the strong suppression o…
Warm Dark Matter meets Cold Dark Matter Isocurvature
Sai Chaitanya Tadepalli, Tomo Takahashi
Isocurvature fluctuations can be generated in various scenarios in the early Universe. In particular, some specific models predict those with a blue-tilted spectrum, which is consi…
More fields are different: Stochastic view of multi-field inflationary scenario
Tomo Takahashi, Koki Tokeshi
High-energy physics often motivates multi-field inflationary scenarios where stochastic effects play a crucial role. Peculiar to multi-field models, the noise-induced centrifugal f…