Revision 1

Accepted · first revision · record

Title: Nonperturbative content of closed superstring field theory
Plain: String field theory writes string theory like an ordinary field theory and fixes many subtle quantities. Whether it defines string theory beyond the weak-coupling series is unknown.
Precise: Closed superstring field theory gives a consistent perturbative definition, including D-instanton contributions with fixed normalizations (Sen 2020-2024). Determine whether it admits classical solutions describing distant backgrounds (full background independence) and a nonperturbative formulation beyond the $g_{s}$ expansion.
Settled by: Construction of a classical solution of closed string field theory describing a background at finite distance in moduli space, or a nonperturbative definition of its path integral.
Kind: well-posed
Answer type: yes-no
References: (empty)
Literature status: open
Status note: Background independence is shown only for nearby backgrounds (Sen and Zwiebach, 1993-1994); D-instanton normalizations computed since 2020 match dual predictions.
Posed since: (empty)