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Bibliographic Details
Main Author: Watson, James D.
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2411.04240
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Table of Contents:
  • The quantum stochastic drift protocol, also known as qDRIFT, has become a popular algorithm for implementing time-evolution of quantum systems using randomised compiling. In this work we develop qFLO, a higher order randomised algorithm for time-evolution. To estimate an observable expectation value at time $T$ to precision $ε$, we show it is sufficient to use circuit depths of $O(T^2\log(1/ε))$ -- an exponential improvement over standard qDRIFT requirements with respect to $ε$. The protocol achieves this using $O(1/ε^2)$ repeated runs of the standard qDRIFT protocol combined with classical post-processing in the form of Richardson extrapolation. Notably, it requires no ancillary qubits or additional control gates making it especially promising for near-term quantum devices. Furthermore, it is well-conditioned and inherits many desirable properties of randomly compiled simulation methods, including circuit depths that do not explicitly depend on the number of terms in the Hamiltonian.