Analytical lower bound on the number of queries to a black-box unitary operation in deterministic exact transformations of unknown unitary operations

Several counter-intuitive go-theorems have recently been shown for transformations of unknown unitary operations; deterministic and exact complex conjugation, inversion, and transposition of a general d-dimensional unknown unitary operation are implementable with a finite number of queries of the black-box unitary operation. However, the minimum numbers of the required queries are not known except for $d=2$ unitary inversion and unitary transposition (numerical) and unitary conjugation (analytic). In this work, we derive complementary no-go theorems for deterministic and exact implementations of inversion and transposition of a d-dimensional unknown unitary operation under certain numbers of queries. The obtained no-go theorem indicates that the analytical lower bound of the number of queries for unitary inversion is d² and that for unitary transposition is $4$ for $d=2$ and $d+3$ for d ≥ 3. We have developed a new framework that utilizes differentiation to obtain the analytical lower bounds on the number of queries to the black-box unitary operation required to implement a transformation given by a general differentiable function mapping a unitary operation to another unitary operation, which reproduces the lower bound of the number of queries for unitary complex conjugation $d-1$. As a corollary, we show the relationship between the tightness of the lower bounds and the existence of optimal catalytic transformations, which is a new aspect recently identified in the study of deterministic and exact unitary inversion. Furthermore, we extend our framework to the probabilistic setting where the transformation is required to succeed with a certain probability, thereby showing a possible tradeoff relation between query numbers and the required success probability.