We present a new open superstring field theory, whose string fields carry an arbitrary picture number and reside in the large Hilbert space. The redundancy related to picture number is resolved by treating picture changing as a gauge transformation. A mid-point insertion is imperative for this formalism. We find that this mid-point insertion must include all multi-picture-changing operators. It is also proven that this insertion as well as all the multi-picture-changing operators are zero weight conformal primaries. This new theory solves the problems with the Ramond sector shared by other Ramond-Neveu-Schwarz (RNS) string field theories, while naturally unifying the Neveu-Schwarz (NS) and Ramond string fields. When partially gauge fixed, it reduces in the NS sector to the modified cubic superstring field theory. Hence, it shares all the good properties of this theory, e.g., it has analytical vacuum and marginal deformation solutions. Treating the redundant gauge symmetry using the Batalin-Vilkovisky (BV) formalism is straightforward and results in a cubic action with a single string field, whose quantum numbers are unconstrained. The generalization to an arbitrary brane system is simple and includes the standard Chan–Paton factors and the most general string field consistent with the brane system.
Michael Kroyter. "Superstring field theory in the democratic picture." Adv. Theor. Math. Phys. 15 (3) 741 - 781, June 2011.