On the Integrability of large N Plane-Wave Matrix Theory
Thomas Klose, Jan Plefka
TL;DR
The paper investigates whether the integrable structure observed at planar, one-loop level in N=4 SYM persists at higher (three) loops within a reduced, large-N plane-wave matrix theory in the SU(2) scalar subsector. Using degenerate perturbation theory and a careful mapping to the SYM dilatation operator, the authors demonstrate three-loop integrability in the planar limit, contingent on a renormalized mass-coupling relation, and show the resulting spectra exhibit parity-degenerate pairs due to a hidden commuting charge. They provide explicit planar dilatation operators and parity-degenerate state constructions, and verify integrability remains robust under certain nonsupersymmetric deformations, though not universally across all bosonic deformations. The work thus supports the conjectured three-loop integrability of planar N=4 SYM and clarifies the role of mass renormalization and deformation stability in the corresponding large-N quantum mechanics.
Abstract
We show the three-loop integrability of large N plane-wave matrix theory in a subsector of states comprised of two complex light scalar fields. This is done by diagonalizing the theory's Hamiltonian in perturbation theory and taking the large N limit. At one-loop level the result is known to be equal to the Heisenberg spin-1/2 chain, which is a well-known integrable system. Here, integrability implies the existence of hidden conserved charges and results in a degeneracy of parity pairs in the spectrum. In order to confirm integrability at higher loops, we show that this degeneracy is not lifted and that (corrected) conserved charges exist. Plane-wave matrix theory is intricately connected to N=4 Super Yang-Mills, as it arises as a consistent reduction of the gauge theory on a three-sphere. We find that after appropriately renormalizing the mass parameter of the plane-wave matrix theory the effective Hamiltonian is identical to the dilatation operator of N=4 Super Yang-Mills theory in the considered subsector. Our results therefore represent a strong support for the conjectured three-loop integrability of planar N=4 SYM and are in disagreement with a recent dual string theory finding. Finally, we study the stability of the large N integrability against nonsupersymmetric deformations of the model.
