RQC Seminar

192nd RQC Seminar

• Speaker

  Dr. Xiao Shuixin
  ( Australian National University )

• Date

  14:30-15:30 (2:30 p.m. - 3:30 p.m.), April 10, 2025 (Thursday)

• Venue

  Hybrid(ZOOM・ Wako Main Research 3F 345-347 Seminar Room / 研究本館3階 セミナー室 (345-347) (C01))

• Title

  Quantum Tomography: Theory, Algorithm, and Experimental Validation

• Inquiries

  norilab_rqc_assist[at]ml.riken.jp

Abstract
Quantum tomography is a fundamental technique for characterizing, benchmarking, and verifying quantum systems and devices, playing a crucial role in advancing quantum technology and exploring the foundations of quantum mechanics. Achieving high accuracy is a fundamental task in quantum tomography, and elucidating the optimality condition remains a core open problem. In this talk, I will present a unified characterization of the estimation accuracy using infidelity metric in quantum state, detector and process tomography. Under this framework, we establish a sufficient and necessary condition for achieving the optimal infidelity scaling O(1/N) after consuming N state copies, which provides a useful guideline for designing optimal tomography algorithms. We develop algorithms that achieve this optimal scaling for quantum state, detector, and process tomography. Additionally, we introduce a framework for jointly estimating quantum states and detectors, independent of state preparation and measurement errors. Moreover, we investigate collective quantum state tomography and propose enhanced algorithms to improve its accuracy. The effectiveness of our approaches is demonstrated through numerical and experimental results.