A new real tachyon vacuum solution in cubic superstring field theory

In this paper, we present a new real tachyon vacuum solution in cubic superstring field theory, constructed without square roots or phantom terms. Although gauge equivalence to known nonreal solutions might suggest identical physical observables, this correspondence is not guaranteed: even in the bosonic theory, gauge-equivalent solutions can yield divergent or ill-defined results for physical quantities. In the supersymmetric case, the situation is further complicated by the presence of the picture-changing operator in the definition of the action and inner product, which requires careful treatment. Building on the [Formula: see text] algebra, our square-root-free solution avoids potential branch cut ambiguities. By explicitly addressing these subtleties, we rigorously compute the vacuum energy and verify that the equation of motion, when contracted with the solution itself, is satisfied. The results confirm consistency with Sen’s conjecture and provide a mathematically consistent foundation for further developments in the construction of analytic, real solutions in superstring field theory.