211th RQC Seminar

• 講演者

  Prof. Wang Xin
  ( Hong Kong University of Science and Technology (Guangzhou) )

• 日程

  2025年7月25日(金), 15:00 - 16:00 (3:00 p.m. - 4:00 p.m.)

• 開催場所

  オンサイト（ Wako Welfare & Conference 2F Large Meeting Room / 統合支援施設2階 大会議室 (C61))

• 講演タイトル

  Reversing Unknown Quantum Evolutions and Processes

• お問合せ

  rqc_info[at]ml.riken.jp

講演概要
Reversing an unknown unitary evolution remains a formidable challenge, as conventional methods necessitate an infinite number of queries to fully characterize the quantum process. Here we introduce the Quantum Unitary Reversal Algorithm, a deterministic and exact approach to universally reverse arbitrary unknown unitary transformations using O(d^2) calls of the unitary, where d is the system dimension. Our construction resolves a fundamental problem of time-reversal simulations for closed quantum systems by affirming the feasibility of reversing any unitary evolution without knowing the exact process. The algorithm also provides the construction of a key oracle for unitary inversion in quantum algorithm frameworks such as quantum singular value transformation. We also propose the framework of virtual combs that exploit the unknown process iteratively with additional classical post-processing to simulate the quantum process inverse and discuss the applications for error mitigation (based on arXiv:2403.04704 and arXiv:2401.04672). Biography: Xin Wang, an Associate Professor at the AI Thrust, The Hong Kong University of Science and Technology (Guangzhou), focuses on quantum information and quantum computing research. He previously worked as a Senior Researcher at Baidu Research, where he led the development of the quantum machine learning platform Paddle Quantum. Before joining Baidu, he was a Hartree Fellow at the University of Maryland. Wang earned his Ph.D. from the University of Technology Sydney in 2018, receiving the Chancellor's Outstanding Thesis Award. He has served as an editor for Quantum and IEEE Transactions on Information Theory.