Abstract

We propose the concept ofpseudo-random quantum states, which appear random to any quantumpolynomial-time adversary. It offers a computational approximation to perfectlyrandom quantum states analogous in spirit to cryptographic pseudo-randomgenerators, as opposed to statistical notions of quantum pseudo-randomness thathave been studied previously, such as quantum t-designs analogous to t-wiseindependent distributions.

Under the assumption thatquantum-secure one-way functions exist, we present efficient constructions ofpseudorandom states, showing that our definition is achievable. We then proveseveral basic properties of pseudo-random states, which show the utility of ourdefinition. First, we show a cryptographic no-cloning theorem: no efficientquantum algorithm can create additional copies of a pseudo-random state, whengiven polynomially-many copies as input. Second, as expected for random quantumstates, we show that pseudo-random quantum states are highly entangled onaverage. Finally, as a main application, we prove that any family ofpseudo-random states naturally gives rise to a private-key quantum moneyscheme.

Time

1月3日（周四）14:00-15:00

Speaker

Zhengfeng Ji iscurrently a Professor of the Centre for Quantum Software and Information (QSI),Faculty of Engineering and Information Technology (FEIT), University ofTechnology Sydney. He received BEng and PhD from the Department of ComputerScience and Technology, Tsinghua University, Beijing, China in 2002 and 2007.His current research interests include quantum algorithms, quantum complexitytheory and (post-)quantum cryptography.

Venue

信息管理与工程学院602室

上海财经大学（第三教学楼西侧）

上海市杨浦区武东路100号