2025/04/20 by Satyaki Manna, Anandamay Das Bhowmik, Manna, Satyaki +3 · 3 citations
Computer Science · Physics and Astronomy · #FOS: Physical sciences #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum Physics (quant-ph)
paper · doi:10.48550/arxiv.2504.14499
openalex publication_date 2025/04/20 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
There have been many instances where the maximally entangled state as a probe acts better than the product and the non-maximally entangled states in the task of distinguishing quantum channels. We provide a proof that for single-shot discrimination of two unitary channels, entangled and product states are operationally equivalent. But we identify pairs of unitaries that are perfectly distinguishable using a non-maximally entangled state, but not with a maximally entangled one. This contrast becomes more pronounced when the number of unitaries exceeds two. In every dimension \geqslant 3, we show that there exists a class of unitaries that are indistinguishable under maximally entangled probes, yet perfectly distinguishable using product or non-maximally entangled inputs. Another interesting set of unitaries in every dimension \geqslant 3 has been presented where only non-maximally entangled state acts as the successful probe, while product states and maximally entangled states cannot.