Overhead for simulating a non-local channel with local channels by quasiprobability sampling

Kosuke Mitarai; Keisuke Fujii

doi:10.22331/q-2021-01-28-388

Overhead for simulating a non-local channel with local channels by quasiprobability sampling

Kosuke Mitarai^1,2,3 and Keisuke Fujii^1,2,4

¹Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan.
²Center for Quantum Information and Quantum Biology, Institute for Open and Transdisciplinary Research Initiatives, Osaka University, Japan.
³JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
⁴Center for Emergent Matter Science, RIKEN, Wako Saitama 351-0198, Japan

Published:	2021-01-28, volume 5, page 388
Eprint:	arXiv:2006.11174v2
Doi:	https://doi.org/10.22331/q-2021-01-28-388
Citation:	Quantum 5, 388 (2021).

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Abstract

As the hardware technology for quantum computing advances, its possible applications are actively searched and developed. However, such applications still suffer from the noise on quantum devices, in particular when using two-qubit gates whose fidelity is relatively low. One way to overcome this difficulty is to substitute such non-local operations by local ones. Such substitution can be performed by decomposing a non-local channel into a linear combination of local channels and simulating the original channel with a quasiprobability-based method. In this work, we first define a quantity that we call channel robustness of non-locality, which quantifies the cost for the decomposition. While this quantity is challenging to calculate for a general non-local channel, we give an upper bound for a general two-qubit unitary channel by providing an explicit decomposition. The decomposition is obtained by generalizing our previous work whose application has been restricted to a certain form of two-qubit unitary. This work develops a framework for a resource reduction suitable for first-generation quantum devices.

► BibTeX data

@article{Mitarai2021overheadsimulating,
  doi = {10.22331/q-2021-01-28-388},
  url = {https://doi.org/10.22331/q-2021-01-28-388},
  title = {Overhead for simulating a non-local channel with local channels by quasiprobability sampling},
  author = {Mitarai, Kosuke and Fujii, Keisuke},
  journal = {{Quantum}},
  issn = {2521-327X},
  publisher = {{Verein zur F{\"{o}}rderung des Open Access Publizierens in den Quantenwissenschaften}},
  volume = {5},
  pages = {388},
  month = jan,
  year = {2021}
}

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