Nature Communications (Oct 2024)

Snapshotting quantum dynamics at multiple time points

  • Pengfei Wang,
  • Hyukjoon Kwon,
  • Chun-Yang Luan,
  • Wentao Chen,
  • Mu Qiao,
  • Zinan Zhou,
  • Kaizhao Wang,
  • M. S. Kim,
  • Kihwan Kim

DOI
https://doi.org/10.1038/s41467-024-53051-5
Journal volume & issue
Vol. 15, no. 1
pp. 1 – 13

Abstract

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Abstract Measurement-induced state disturbance is a major challenge in obtaining quantum statistics at multiple time points. We propose a method to extract dynamic information from a quantum system at intermediate time points, namely snapshotting quantum dynamics. To this end, we apply classical post-processing after performing the ancilla-assisted measurements to cancel out the impact of the measurements at each time point. Based on this, we reconstruct a multi-time quasi-probability distribution (QPD) that correctly recovers the probability distributions at the respective time points. Our approach can also be applied to simultaneously extract exponentially many correlation functions with various time-orderings. We provide a proof-of-principle experimental demonstration of the proposed protocol using a dual-species trapped-ion system by employing 171Yb+ and 138Ba+ ions as the system and the ancilla, respectively. Multi-time measurements are performed by repeated initialization and detection of the ancilla state without directly measuring the system state. The two- and three-time QPDs and correlation functions are reconstructed reliably from the experiment, negativity and complex values in the QPDs clearly indicate a contribution of the quantum coherence throughout dynamics.