A divide-and-conquer algorithm for quantum state preparation

Israel F. Araujo, Daniel K. Park, Francesco Petruccione, Adenilton J. da Silva

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)


Advantages in several fields of research and industry are expected with the rise of quantum computers. However, the computational cost to load classical data in quantum computers can impose restrictions on possible quantum speedups. Known algorithms to create arbitrary quantum states require quantum circuits with depth O(N) to load an N-dimensional vector. Here, we show that it is possible to load an N-dimensional vector with exponential time advantage using a quantum circuit with polylogarithmic depth and entangled information in ancillary qubits. Results show that we can efficiently load data in quantum devices using a divide-and-conquer strategy to exchange computational time for space. We demonstrate a proof of concept on a real quantum device and present two applications for quantum machine learning. We expect that this new loading strategy allows the quantum speedup of tasks that require to load a significant volume of information to quantum devices.

Original languageEnglish
Article number6329
JournalScientific reports
Issue number1
Publication statusPublished - 2021 Dec

Bibliographical note

Publisher Copyright:
© 2021, The Author(s).

All Science Journal Classification (ASJC) codes

  • General


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