Effective String Theory Revisited

TL;DR

This paper revisits the effective field theory of relativistic strings, deriving key interactions and explaining how non-critical strings gain excitations in orthogonal directions through one-loop calculations.

Contribution

It derives the Polchinski-Strominger interaction in static gauge and clarifies the role of counterterms in regularization methods for string effective actions.

Findings

Derived the Polchinski-Strominger interaction via static gauge calculation.

Showed non-critical strings gain orthogonal excitations without extra terms.

Explained the necessity of non-covariant counterterms in zeta-function regularization.

Abstract

We revisit the effective field theory of long relativistic strings such as confining flux tubes in QCD. We derive the Polchinski-Strominger interaction by a calculation in static gauge. This interaction implies that a non-critical string which initially oscillates in one direction gets excited in orthogonal directions as well. In static gauge no additional term in the effective action is needed to obtain this effect. It results from a one-loop calculation using the Nambu-Goto action. Non-linearly realized Lorentz symmetry is manifest at all stages in dimensional regularization. We also explain that independent of the number of dimensions non-covariant counterterms have to be added to the action in the commonly used zeta-function regularization.