Quantum / CONCEPT

Achievable (k-fidelity, process fidelity) regions and single-fidelity non-identifiability

Exact planar regions of pairs (F_k(Lambda), F(Lambda)) realized by n-qubit completely positive trace-preserving maps across k = 0, 1 <= k <= n - 1, and k >= n, closed-form upper and lower process-fidelity envelopes at prescribed 0-fidelity, unimodal maximizer analysis of the binomial weight kernel, and non-identifiability of F(Lambda) from any single F_k(Lambda) for n >= 2 and k <= n - 1.