Membrane Action via Orbifold

We propose a new Lagrangian describing N = 4 superconformal field theory in three dimensions. This theory describes interacting field theory on the worldvolume of a M2brane on an orbifold, and is obtained as a Z2-quotient of the theory proposed by Bagger and Lambert. Despite unusual Chan-Paton structures, we can take Z2-orbifold by using SU(2) × SU(2) bifundamental representations. We also analyze the moduli space of this theory and found three branches. When the level of Chern-Simons is k = 1, the moduli space is consistent with that of the D2-brane in the strong coupling limit of Type IIA string theory if the gauge group is O(4). Our action has manifest Z2-symmetry exchanging two R/Z2’s in M-theory, and this suggests a new non-perturbative duality between a O2-brane on orbifold R/Z2 and a O2 -brane with D6-branes. hfuji(at)yukawa.kyoto-u.ac.jp terasima(at)yukawa.kyoto-u.ac.jp yamazaki(at)hep-th.phys.s.u-tokyo.ac.jp