Gauge fixing in higher derivative field theories

TL;DR

This paper explores gauge fixing in higher derivative field theories, demonstrating how such theories can be transformed into second order forms and analyzing the implications for gauge fixing and ghost fields, with insights applicable to gravity theories.

Contribution

It provides a detailed analysis of gauge fixing procedures in higher derivative theories and clarifies the nature of the 'third ghost' in these contexts.

Findings

Higher derivative theories can be equivalently reformulated as second order theories.

Gauge fixing in HD theories involves a 'third ghost' phenomenon.

Insights gained are relevant for HD gravity and gauge theories.

Abstract

Higher Derivative (HD) Field Theories can be transformed into second order equivalent theories with a direct particle interpretation. In a simple model involving abelian gauge symmetries we examine the fate of the possible gauge fixings throughout this process. This example is a useful test bed for HD theories of gravity and provides a nice intuitive interpretation of the "third ghost" occurring there and in HD gauge theories when a HD gauge fixing is adopted.