Non-minimally coupled inflation is an inflationary

Cosmic inflation

In physical cosmology, cosmic inflation, cosmological inflation or just inflation is the theorized extremely rapid exponential expansion of the early universe by a factor of at least 1078 in volume, driven by a negative-pressure vacuum energy density. The inflationary epoch comprises the first part...

 model in which the constant which couples gravity to the inflaton field is not small. The coupling constant

Coupling constant

In physics, a coupling constant, usually denoted g, is a number that determines the strength of an interaction. Usually the Lagrangian or the Hamiltonian of a system can be separated into a kinetic part and an interaction part...

 is usually represented by , which features in the action

Action (physics)

In physics, action is an attribute of the dynamics of a physical system. It is a mathematical functional which takes the trajectory, also called path or history, of the system as its argument and has a real number as its result. Action has the dimension of energy × time, and its unit is...

 (constructed by modifying the Einstein-Hilbert action

Einstein-Hilbert action

The Einstein–Hilbert action in general relativity is the action that yields the Einstein's field equations through the principle of least action...

):



represents the strength of the interaction between and , which relate to the curvature of space and the magnitude of the inflaton field respectively.