Multi-brid DBI Inflation

TL;DR

This paper extends the multi-brid $ abla$N formalism to non-canonical multi-field models, specifically the DBI inflation, deriving explicit e-folds expressions and cosmological parameters for different sound speed regimes.

Contribution

It introduces a novel application of $ abla$N formalism to the DBI inflation model, providing explicit formulas for e-folds and cosmological parameters in non-canonical multi-field scenarios.

Findings

Derived explicit e-folds expressions for DBI inflation.

Analyzed cosmological parameters in speed limit and constant sound speed limits.

Extended multi-brid $ abla$N formalism to non-canonical multi-field models.

Abstract

It is shown that it is possible to apply $\delta \cN$ to some special non-canonic cases. We extended the multi-brid idea to the multi-field separable model with a non-canonical kinetic term, mainly the DBI model. Assuming a specific surface for the end of inflation and introducing new fields, enable us to find an explicit expression for the number of e-folds in terms of the new fields. By using $\delta$N formalism, we arrived at the cosmological parameters. We considered the DBI model for two different limits, viz., speed limit and constant sound speed.