Non-linear theory for multiple M2 branes

We present a manifestly SO( 8) invariant non-linear Lagrangian for describing the non-abelian dynamics of the bosonic degrees of freedom of N coinciding M2 branes in flat spacetime. The theory exhibits a gauge symmetry structure of the BF type (semidirect product of SU( N) and translations) and at low energies it reduces exactly to the bosonic part of the Lorentzian Bagger-Lambert Lagrangian for group SU( N). There are eight scalar fields satisfying a free-scalar equation. When one of them takes a large expectation value, the non-linear Lagrangian gets simplified and the theory can be connected to the non-abelian Lagrangian describing the dynamics of N coinciding D2 branes. As an application, we show that the BPS fuzzy funnel solution describing M2 branes ending on a single M5 brane is an exact solution of the non-linear system.