Ultra slow-roll inflation demystified

Key Points

• This research aims to clarify the dynamics of ultra-slow-roll inflation and its conditions of occurrence.
• Analyzed the properties of ultra-slow-roll inflation in relation to scalar potential shape.
• Estimated the duration of ultra-slow-roll inflation based on initial kinetic density.
• Assessed the threshold conditions under which ultra-slow-roll can be avoided.
• US inflation occurs when the inflaton field traverses a flat scalar potential for extended periods.
• If the initial kinetic density is sufficiently low, standard slow-roll inflation applies instead.
• Findings have crucial implications for models involving inflection-point inflation.