---
tags: VQE, NISQ, Noise, Numerical
sort-date: 2024-01-27
description: We benchmark the response to noise of a range of VQE algorithms.
---

Kieran Dalton<a href="https://orcid.org/0009-0006-2416-356X"><font color="#a6ce39"><i class='fa-brands fa-orcid'></i></font></a>,
[[/index|Christopher K. Long]]<a href="https://orcid.org/0009-0001-3230-942X"><font color="#a6ce39"><i class='fa-brands fa-orcid'></i></font></a>,
Yordan S. Yordanov<a href="https://orcid.org/0000-0002-3828-0090"><font color="#a6ce39"><i class='fa-brands fa-orcid'></i></font></a>,
Charles G. Smith<a href="https://orcid.org/0000-0002-5611-0095"><font color="#a6ce39"><i class='fa-brands fa-orcid'></i></font></a>,
Crispin H. W. Barnes<a href="https://orcid.org/0000-0001-7337-7245"><font color="#a6ce39"><i class='fa-brands fa-orcid'></i></font></a>,
Normann Mertig<a href="https://orcid.org/0000-0003-3025-7141"><font color="#a6ce39"><i class='fa-brands fa-orcid'></i></font></a>,
and David R. M. Arvidsson-Shukur<a href="https://orcid.org/0000-0002-0185-0352"><font color="#a6ce39"><i class='fa-brands fa-orcid'></i></font></a>

Published: 27 January 2024

DOI: [10.1038/s41534-024-00808-x](https://doi.org/10.1038/s41534-024-00808-x)

[[PDFs/Quantifying the effect of gate errors on variational quantum eigensolvers for quantum chemistry.pdf|PDF Download]]

[[PDFs/Supplementary Information for: Quantifying the effect of gate errors on variational quantum eigensolvers for quantum chemistry.pdf|Supplementary Information PDF Download]]

# Abstract

> Variational quantum eigensolvers (VQEs) are leading candidates to demonstrate near-term quantum advantage. Here, we conduct density-matrix simulations of leading gate-based VQEs for a range of molecules. We numerically quantify their level of tolerable depolarizing gate-errors. We find that: (i) The best-performing VQEs require gate-error probabilities between 10<sup>−6</sup> and 10<sup>−4</sup> (10<sup>−4</sup> and 10<sup>−2</sup> with error mitigation) to predict, within chemical accuracy, ground-state energies of small molecules with 4–14 orbitals. (ii) ADAPT-VQEs that construct ansatz circuits iteratively outperform fixed-circuit VQEs. (iii) ADAPT-VQEs perform better with circuits constructed from gate-efficient rather than physically-motivated elements. (iv) The maximally-allowed gate-error probability, $p_c$, for any VQE to achieve chemical accuracy decreases with the number $N_\text{II}$ of noisy two-qubit gates as $p_c \underset{\sim}{\propto} N_\text{II}$. Additionally, $p_c$ decreases with system size, even with error mitigation, implying that larger molecules require even lower gate-errors. Thus, quantum advantage via gate-based VQEs is unlikely unless gate-error probabilities are decreased by orders of magnitude.

# Citation

Kieran Dalton, Christopher K. Long, Yordan S. Yordanov, Charles G. Smith, Crispin H. W. Barnes, Normann Mertig, and David R. M. Arvidsson-Shukur. Quantifying the effect of gate errors on variational quantum eigensolvers for quantum chemistry, *npj Quantum Inf* **10**, 18 (2024), DOI: [10.1038/s41534-024-00808-x](https://doi.org/10.1038/s41534-024-00808-x).

## BibTeX

```bibtex
@article{Dalton2024,
    author={Dalton, Kieran
    and Long, Christopher K.
    and Yordanov, Yordan S.
    and Smith, Charles G.
    and Barnes, Crispin H. W.
    and Mertig, Normann
    and Arvidsson-Shukur, David R. M.},
    title={Quantifying the effect of gate errors on variational quantum eigensolvers for quantum chemistry},
    journal={npj Quantum Information},
    year={2024},
    month={Jan},
    day={27},
    volume={10},
    pages={18},
    issn={2056-6387},
    doi={10.1038/s41534-024-00808-x},
    url={https://doi.org/10.1038/s41534-024-00808-x}
}
```

# Other versions

- Tue, 13 Feb 2024 17:30:41 UTC: [*https://arxiv.org/abs/2211.04505v2*](https://arxiv.org/abs/2211.04505v2). Downloads: [[PDFs/2211.04505v2.pdf|PDF]], [[TeX_Source/2211.04505v2.tar.gz|TeX Source]]
- Tue, 8 Nov 2022 19:05:38 UTC: [*https://arxiv.org/abs/2211.04505v1*](https://arxiv.org/abs/2211.04505v1). Downloads: [[PDFs/2211.04505v1.pdf|PDF]], [[TeX_Source/2211.04505v1.tar.gz|TeX Source]]

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