Experimental Quantum State Measurement with Classical Shadows

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

3 Scopus Citations
View graph of relations

Author(s)

  • Ting Zhang
  • Jinzhao Sun
  • Xiao-Xu Fang
  • Xiao Yuan
  • He Lu

Related Research Unit(s)

Detail(s)

Original languageEnglish
Article number200501
Journal / PublicationPhysical Review Letters
Volume127
Issue number20
Online published8 Nov 2021
Publication statusPublished - 12 Nov 2021

Abstract

A crucial subroutine for various quantum computing and communication algorithms is to efficiently extract different classical properties of quantum states. In a notable recent theoretical work by Huang, Kueng, and Preskill [Nat. Phys. 16, 1050 (2020)], a thrifty scheme showed how to project the quantum state into classical shadows and simultaneously predict M different functions of a state with only O(log2M) measurements, independent of the system size and saturating the information-theoretical limit. Here, we experimentally explore the feasibility of the scheme in the realistic scenario with a finite number of measurements and noisy operations. We prepare a four-qubit GHZ state and show how to estimate expectation values of multiple observables and Hamiltonians. We compare the measurement strategies with uniform, biased, and derandomized classical shadows to conventional ones that sequentially measure each state function exploiting either importance sampling or observable grouping. We next demonstrate the estimation of nonlinear functions using classical shadows and analyze the entanglement of the prepared quantum state. Our experiment verifies the efficacy of exploiting (derandomized) classical shadows and sheds light on efficient quantum computing with noisy intermediate-scale quantum hardware.

Citation Format(s)

Experimental Quantum State Measurement with Classical Shadows. / Zhang, Ting; Sun, Jinzhao; Fang, Xiao-Xu; Zhang, Xiao-Ming; Yuan, Xiao; Lu, He.

In: Physical Review Letters, Vol. 127, No. 20, 200501, 12.11.2021.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review