Dissipation during inflation

Abstract: I will discuss phenomena associated with particle production and field excitation during inflation. In the first part of the talk I will present several signatures that can originate from the coupling of an axion inflaton to gauge fields. In the second part I will test the robustness of the standard implications associated with the detection of a gravity wave (GW) signal at CMB scales, by discussing what conditions can allow a visible sourced GW background that exceeds the vacuum one (without simultaneously overproduce scalar perturbations), and by providing a concrete example. In the final part I will review the phenomenology of trapped inflation, which is an interesting and minimal mechanism where particle production provides the main friction for the motion of the inflaton.