Interpreting the M2-brane Action

TL;DR

This paper interprets the scalar field in the M2-brane world-volume theory as the radial position of the branes, linking it to D2-branes with a radial-dependent Yang-Mills coupling and confirming this through derived equations of motion.

Contribution

It proposes a new geometric interpretation of the scalar field in M2-brane theory as a radial coordinate, connecting M2-branes to D2-branes in type IIA string theory.

Findings

The scalar field acts as the radial position of M2-branes.

The Yang-Mills coupling varies with the radial coordinate.

The radial coordinate satisfies free field equations.

Abstract

The world-volume theory of multiple M2-branes proposed recently has a free scalar field. For large vev of this scalar field the world-volume action reduces to that of multiple D2-branes with Yang-Mills coupling proportional to the vev. We suggest that the correct interpretation of this scalar field is as the radial position of the M2-brane center of mass in a cylindrical polar coordinate system. Regarding the azimuthal angle as compact we can regard this as a set of coincident D2-branes in type IIA string theory with varying dilaton and metric. We find that the effective world-volume theory on the D2-branes has Yang-Mills coupling proportional to the radial coordinate; furthermore the radial coordinate satisfies free field equations of motion. This agrees with the corresponding results derived from the M2-brane world-volume theory.