## Chapter 4 

## A New Thermal Inflation Model 

## 4.1 Thermal Inflation 

Thermal Inflation [47–50] is a brief period of inflation (lasting about 10 e- folds) that could have occurred after a period of prior primordial inflation. It occurs due to finite-temperature effects arising from a coupling between a thermal waterfall field and the thermal bath created from the partial or com- plete reheating from the prior inflation. If we start with a zero-temperature scalar field theory, we can calculate the affect that placing the system in a thermal bath at temperature T has on the theory by introducing an inter- action term in the form of a 1-loop correction. After calculating the appro- priate variables within the context of thermal field theory, we can take the high- T approximation of the correction, which gives a thermal contribution V$_{T}$ ≃ g $^{2}$T $^{2}$φ2 to the effective potential V$_{eff}$ , where g is the coupling constant 

