4 papers
No Universal Purification in Quantum Mechanics
Zhenhuan Liu, Zhenyu Du, Jens Eisert +2
Many central tasks in fundamental physics and quantum information processing are possible only insofar as mixed quantum states can be made purer. In this work, we prove that the li…
Certifying localizable quantum properties with constant sample complexity
Zhenyu Du, Jinchang Liu, Elias X. Huber +2
Characterizing increasingly complex quantum systems is a central task in quantum information science, yet experimental costs often scale prohibitively with system size. Certifying…
Optimal randomized measurements for a family of non-linear quantum properties
Zhenyu Du, Yifan Tang, Andreas Elben +3
Quantum learning encounters fundamental challenges when estimating non-linear properties, owing to the inherent linearity of quantum mechanics. Although recent advances in single-c…
Exponential Separations between Quantum Learning with and without Purification
Zhenhuan Liu, Weiyuan Gong, Zhenyu Du +1
In quantum learning tasks, quantum memory can offer exponential reductions in statistical complexity compared to any single-copy strategies, but this typically necessitates at leas…