Baek, Kyunghyun
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Kyunghyun Baek studied physics at Sogang University, where he received his B.S. in 2012 and his Ph.D. in 2018 with a thesis on entropic uncertainty relations, unsharpness, and non-Gaussianity. He then worked as a postdoctoral researcher at Texas A&M University at Qatar and the Asia Pacific Center for Theoretical Physics, and later joined the Korea Institute for Advanced Study as a Research Fellow. From 2022 to 2024, he was a Senior Researcher at the Electronics and Telecommunications Research Institute. In 2024, he became Assistant Professor at Yonsei University, Institute for Convergence Research and Education in Advanced Technology, and Head of the Center for Quantum Computing Technology Support in Incheon. His research focuses on quantum information theory, quantum measurement, quantum resource theories, and near-term quantum algorithms, including variational quantum algorithms, quantum simulation, and quantum computing applications.
Maximal coherence of quantum measurement and the resource theory of sharpness
- Speaker: Kyunghyun Baek (Yonsei University, Korea)
- Event: Quantum Technology Workshop 2026
A resource theory of quantum measurement can be addressed in terms of quantum coherence and measurement sharpness, respectively. The former analyzes the off-diagonal structure of POVM elements in a predetermined basis while the latter analyzes the deviation from trivial, state-independent, measurements. In this talk, I will review the framework of quantum resource theories, and introduce a direct connection between the two resource theories by identifying measurement sharpness as the maximal coherence that is achievable under all possible unitary changes of the reference basis. More specifically, for a broad class of POVMs whose elements share a common eigenbasis, we show that the maximal distance-based coherence of measurement coincides exactly with the corresponding distance-based sharpness monotone. We further extend this equivalence, with element-additive distances, to POVMs whose elements admit a common mutually unbiased basis structure. These results provide a measurement-theoretic analogue of the maximal-coherence and purity correspondence for quantum states.