--- tags: VQE, Hamiltonian-level, NISQ, Numerical sort-date: 2025-07-05 description: We numerically estimate the minimum evolution time for a range of state-preparation tasks on silicon spin-qubit quantum processors. --- [[/index|Christopher K. Long]], Nicholas J. Mayhall, Sophia E. Economou, Edwin Barnes, Crispin H. W. Barnes, Frederico Martins, David R. M. Arvidsson-Shukur, and Normann Mertig Published: 5 July 2025 DOI: [10.1038/s41534-025-01027-8](https://doi.org/10.1038/s41534-025-01027-8) [[PDFs/Minimal state-preparation times for silicon spin qubits.pdf|PDF Download]] [[PDFs/Supplementary Information: Minimal state-preparation times for silicon spin qubits.pdf|Supplementary Information PDF Download]] # Abstract > Efficient preparation of quantum states on noisy intermediate-scale quantum processors remains a significant challenge to achieve quantum advantage. While gate-based methods have been the traditional approach, pulse-based algorithms offer promising alternatives with finer control and potentially reduced overheads. Here, we leverage the concept of minimum evolution time (MET) as a fundamental metric for evaluating and benchmarking quantum-state-preparation efficiency. Using numerical modeling, we investigate METs achievable through optimized microwave and exchange pulse sequences on silicon quantum hardware. We focus our investigations on molecular ground states and arbitrary state transitions. Our results demonstrate remarkably low METs: 2.3 ns for H2, 4.6 ns for HeH+, and 27 ns for LiH. METs consistently remain below 50 ns for arbitrary four-qubit state transitions, outperforming gate-based methods. We perform further analyses, revealing the impact of silicon device parameters on MET performance. Notably, increasing the maximal exchange amplitude from 10 MHz to 1 GHz significantly reduces METs, while higher maximal microwave drive amplitudes lead to faster state transitions. These findings surpass results reported for other quantum architectures. Our numerical analysis also demonstrates reasonable robustness of pulse-based state preparation to device imperfections and leakage. Our study contributes to developing efficient quantum-simulation techniques and provides insights into the strengths of silicon quantum hardware. # Citation Christopher K. Long, Nicholas J. Mayhall, Sophia E. Economou, Edwin Barnes, Crispin H. W. Barnes, Frederico Martins, David R. M. Arvidsson-Shukur, and Normann Mertig. Minimal state-preparation times for silicon spin qubits. *npj Quantum Inf* **11**, 113 (2025), DOI: [10.1038/s41534-025-01027-8](https://doi.org/10.1038/s41534-025-01027-8). ## BibTeX ```bibtex @article{Long2025, author={Long, Christopher K. and Mayhall, Nicholas J. and Economou, Sophia E. and Barnes, Edwin and Barnes, Crispin H. W. and Martins, Frederico and Arvidsson-Shukur, David R. M. and Mertig, Normann}, title={Minimal state-preparation times for silicon spin qubits}, journal={npj Quantum Information}, year={2025}, month={Jul}, day={05}, volume={11}, pages={113}, issn={2056-6387}, doi={10.1038/s41534-025-01027-8}, url={https://doi.org/10.1038/s41534-025-01027-8} } ``` # Previous version - Sun, 16 Jun 2024 12:27:21 UTC: [*https://arxiv.org/abs/2406.10913v1*](https://arxiv.org/abs/2406.10913v1). Downloads: [[PDFs/2406.10913v1.pdf|PDF]], [[TeX_Source/2406.10913v1.tar.gz|TeX Source]] # Software - [[/Software/Minimal-state-preparation-times-for-silicon-spin-qubits-source-code/index|Minimal-state-preparation-times-for-silicon-spin-qubits-source-code]] [@long_2025_17340395] - [[/Software/QuGradLab/index|QuGradLab]] [@QuGradLab] - [[/Software/QuGrad/index|QuGrad]] [@QuGrad] - [[/Software/PySTE/index|PySTE]] [@PySTE] - [[/Software/Suzuki-Trotter-Evolver/index|Suzuki-Trotter-Evolver]] [@SuzukiTrotterEvolver] # Data - [[/Datasets/Minimal state-preparation times for silicon spin qubits data]] [@long_2025_15676408] # Analytics - [Google Scholar](https://scholar.google.com/citations?view_op=view_citation&citation_for_view=GRSIcsEAAAAJ:ufrVoPGSRksC) - [SciRate](https://scirate.com/arxiv/2406.10913) - [INSPIRE-HEP](https://inspirehep.net/literature/2943776) - [Semantic Scholar](https://www.semanticscholar.org/paper/Minimal-state-preparation-times-for-silicon-spin-Long-Mayhall/027ac9d81e23bf647219031994763bd1cae5a17f) # Social media posts ## Bluesky > [!Thread] >

How fast can quantum processors run? My coauthors and I answer in our new npj Quantum Information article! Utilising pulse engineering, we prepare molecular ground states in a few nanoseconds, ~100× faster than with gates. Back-of-the-envelope: Simulations can now tolerate T₁ and T₂ ~100× smaller.

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— Christopher K. Long (@christopher-k-long.bsky.social) 5 July 2025 at 11:22
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Preparing molecular ground states for H₂, HeH⁺, and LiH in 2.3, 4.6, and 26.8 ns:

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— Christopher K. Long (@christopher-k-long.bsky.social) 5 July 2025 at 11:29
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Further, we consider random state transitions to bound the performance of arbitrary quantum algorithms. Finally, we study the robustness of the pulse-based approach to device imperfections and leakage:

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— Christopher K. Long (@christopher-k-long.bsky.social) 5 July 2025 at 11:36
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If you liked the preprint, then you should skim through the published version for all the new figures and data. All data and code are publicly available: doi.org/10.5281/zeno... github.com/Christopher-... This data could not have been collected without the libraries we developed for this project:

[image or embed]

— Christopher K. Long (@christopher-k-long.bsky.social) 5 July 2025 at 11:41
## LinkedIn

How fast can quantum processors run? My coauthors—Nicholas Mayhall, Sophia E. Economou, Edwin Barnes, Prof. Crispin H. W. Barnes, Frederico Martins, David Arvidsson-Shukur, and Normann Mertig—and I answer this in our new npj Quantum Information article! https://lnkd.in/eWacHdby Utilising pulse engineering, we prepare molecular ground states in a few nanoseconds, ~100× faster than with gates. Back-of-the-envelope: Simulations can now tolerate T₁ and T₂ ~100× smaller. Further, we consider random state transitions to bound the performance of arbitrary quantum algorithms. Finally, we study the robustness of the pulse-based approach to device imperfections and leakage. If you liked the preprint, then you should skim through the published version for all the new figures and data. All data and code are publicly available—links can be found in the article. This data could not have been collected without the libraries we developed for this project, which I recently posted about. Links to these libraries can be found in the article.

— Christopher K. Long (LinkedIn) 5 July 2025
## X > [!Thread] >

How fast can quantum processors run? We (@nick_mayhall, @see_quantum, et al.) answer in @Nature_NPJ! Using pulse engineering, we prepare molecular ground states in a few ns, 100×faster than gates. Back-of-the-envelope: We can tolerate T₁,T₂ ~100×smaller.https://t.co/khiFC0VON0

— Chris Long (@Chris_K_Long45) July 5, 2025
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Preparing molecular ground states for H₂, HeH⁺, and LiH in 2.3, 4.6, and 26.8 ns: pic.twitter.com/Npxud85ELS

— Chris Long (@Chris_K_Long45) July 5, 2025
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Further, we consider random state transitions to bound the performance of arbitrary quantum algorithms. Finally, we study the robustness of the pulse-based approach to device imperfections and leakage: pic.twitter.com/lIsD6Kea7C

— Chris Long (@Chris_K_Long45) July 5, 2025
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If you liked the preprint, then you should skim through the published version for all the new figures and data. All data and code are publicly available:https://t.co/HqmtljDLKzhttps://t.co/IAOgrkzlq8

— Chris Long (@Chris_K_Long45) July 5, 2025
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This data could not have been collected without the libraries we developed for this project:https://t.co/gfcbKj2fe6

— Chris Long (@Chris_K_Long45) July 5, 2025