In this work, we shall study k-inflation theories with non-minimal coupling of the scalar field to gravity, in presence only a higher-order kinetic term form $$\sim \hbox {const}\times X^{\mu }$$ , $$X=\frac{1}{2}\partial _{\mu } \phi \partial ^{\mu }\phi $$ . The will be focused cases where potential is included or absent, and evolution assumed satisfy slow-roll constant-roll condition. case m...

We explore a new possibility that some inflaton fields in multi-field inflation models satisfy the observed value of the spectral index so that the curvature perturbation generated by them through post-inflationary dynamics may be relevant for the current observations. We illustrate this point using a simple and reasonable multi-field chaotic inflation model motivated from string theory. Possib...

I establish that inflation risk is priced in the cross section of stock returns: Stocks that have low returns during inflationary times command a risk premium. I estimate a market price of inflation risk that is comparable in magnitude to the price of risk for the aggregate market. Inflation is therefore a key determinant of risk in the cross section of stocks. The inflation premium cannot be e...

This paper studies the implication of unit root supply shocks for the Taylor rule. I find that, when supply shocks have a unit root, if a central bank wishes to guarantee the stationarity of inflation, then their interest rate reaction function should not respond to the output gap. Once the stationarity of inflation is guaranteed by the output-gap-response parameter, the ‘‘Taylor principle’’ ca...

The dynamics of a single scalar field which describes a second order phase transition is considered taking into account the thermal effects in the high temperature limit. I conclude that thermal effects play a very important role during inflation and do not must to be ignored in models for the early universe. At the end of inflation thermal fluctuations are more important than quantum fluctuati...