The `unitarity problem' of Higgs inflation in the light of collapse dynamics

Abstract

Higgs inflation scenario is one of the most compelling models of inflation at present time. It not only explains the observed data well, but also provides means to include the inflaton field within the well understood Standard Model of particle physics, without invoking any need for its extension. Despite this, due to the requirement of large non-minimal coupling to the curvature scalar of the inflaton field, or in this case the Higgs field, this model suffers from a problem often called as the `unitarity' or the `naturalness' problem. On the other hand, to address the longstanding `interpretational issue' of quantum to classical transition of the primordial modes, the collapse dynamics of quantum mechanics has recently been included into the inflationary mechanism. We show that inclusion of such collapse mechanism in Higgs inflation helps alleviate the `unitarity problem' to a great deal.

Comments: 14 pgs, no figure, v2 & v3: Discussion of Sec 3.3 slightly modified, changes have been made in the 'Discussion and Conclusion' section accordingly, main conclusion unchanged, references added, accepted for publication in JCAP