Galileon string measure and other modified measure extended objects

TL;DR

This paper introduces a novel formulation of string theory called 'Galileon string theory,' where a galileon field modifies the measure in the action, leading to a theory with second-order equations of motion and dynamical string tension.

Contribution

It develops a new string theory framework incorporating galileon fields into the measure, maintaining second-order equations and revealing a dynamical string tension and galileon symmetry.

Findings

The equations reduce to those of Polyakov string theory.

The string tension becomes a dynamical degree of freedom.

The theory exhibits galileon symmetry explicitly.

Abstract

We show that it is possible to formulate string theory as a "Galileon string theory". The galileon field $\chi$ enters in the definition of the integration measure in the action. Following the methods of the modified measure string theory, we find that the final equations are again those of Polyakov. Moreover, the string tension appears again as an additional dynamical degree of freedom. At the same time the theory satisfies all requirements of the galileon higher derivative theory at the action level while the equations of motion are still of the second order. A galileon symmetry is displayed explicitly in the conformal string worldsheet frame. Also we define the galileon gauge transformations. Generalizations to branes with other modified measures are discussed.