Optimality of isotypic-compression resources

Determine whether the circuit depths and number of ancillae used by the isotypic-compression circuit for stabilizer-state learning are optimal, or whether they can be reduced further.

Background

The algorithm achieves near-optimal sample complexity but relies on an isotypic-compression circuit whose implementation dominates the computational complexity. The paper leaves unresolved whether the stated depth and ancilla requirements are necessary or can be improved.