I am reading "Gauging What's Real" by Richard Healey and the author argues for formulating electrodynamics/QED on loop space/the holonomy group, so that the real objects described by the theory are the Wilson Loops or Dirac phase factors ${ e }^{ \frac { ie }{ \hbar } \oint _{ \gamma }^{ }{ { A }_{ \mu }d{ x }^{ \mu } } }$.
I was wondering if it is possible to formulate Quantum Field Theory (or maybe even Quantum Mechanics) on loop spaces, so that the quantum field/ wave functions take loops as arguments. (I am especially interested if one could formulate Quantum Mechanics in this way).