On light-cone SFT contact terms in a plane wave

TL;DR

This paper computes contact terms in light-cone string field theory within the BMN correspondence, confirming their agreement with gauge theory predictions at order g_2^2 for states with two string excitations.

Contribution

It provides the first explicit calculation of contact terms at large mu p^+ alpha' in light-cone SFT, matching gauge theory results and clarifying supersymmetry's role.

Findings

Contact terms calculated at order g_2^2

Results agree with gauge theory predictions

Clarifies supersymmetry's role in string interactions

Abstract

Testing the BMN correspondence at non-zero string coupling g_s requires a one-loop string field theory calculation. At order g_s^2, matrix elements of the light-cone string field theory Hamiltonian between single-string states receive two contributions: the iterated cubic interaction, and a contact term {Q, Q} whose presence is dictated by supersymmetry. In this paper we calculate the leading large mu p^+ alpha' contribution from both terms for the set of intermediate states with two string excitations. We find precise agreement with the basis-independent order g_2^2 results from gauge theory.