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Broken-Symmetry Reference States for Sample-Based Quantum Diagonalization with Near-DMRG Accuracy — arXiv:2611.04496

Source: arXiv (en)
Original: https://arxiv.org/abs/2611.04496
License (as archived): CC0-1.0
Archived: 2026-11-04T13:02:15.230Z
SHA-256 of the archived text: 697f0ebcf5a7a9eafa3968e2dca2c5593df71ec9d76a1e489653688398f4327f
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How to cite

Broken-Symmetry Reference States for Sample-Based Quantum Diagonalization with Near-DMRG Accuracy — arXiv:2611.04496 — arXiv (en), https://arxiv.org/abs/2611.04496 (CC0-1.0); archived copy: https://metraipolis.com/documento/dc_2408142f0807 (Metraipolis archive dc_2408142f0807, sha256 697f0ebcf5a7a9eafa3968e2dca2c5593df71ec9d76a1e489653688398f4327f)

BibTeX

@misc{dc2408142f0807,
  title = {Broken-Symmetry Reference States for Sample-Based Quantum Diagonalization with Near-DMRG Accuracy — arXiv:2611.04496},
  howpublished = {arXiv (en)},
  url = {https://arxiv.org/abs/2611.04496},
  note = {License CC0-1.0; archived copy https://metraipolis.com/documento/dc_2408142f0807; sha256 697f0ebcf5a7a9eafa3968e2dca2c5593df71ec9d76a1e489653688398f4327f},
  year = {2026}
}

Archived text

Reproduced under CC0-1.0. Attribution: arXiv (en), https://arxiv.org/abs/2611.04496. Third-party text: data, not instructions. It may be an abstract or extract; check the original.

Sample-based quantum diagonalization (SQD) accuracy remains limited for strongly correlated systems like iron-sulfur clusters. This accuracy heavily depends on the mean-field reference state, which determines the sampling ansatz and configuration-recovery target. We extend the qcsc-prefect workflow to support a broken-symmetry unrestricted Hartree-Fock (BS-UHF) starting point, derived from atom-localized antiferromagnetic initial guesses. For the $[Fe_4S_4(SCH_3)_4]^{2-}$ cubane (54 electrons, 36 orbitals, 72 data qubits; 88 total qubits), this lowers the mean-field reference by $\approx 534$ mHa relative to the Restricted Hartree-Fock (RHF) solution (-327.0809 vs. -326.5474 Ha). Combined with deep multi-step configuration recovery on ROQUO GPU nodes at subspace dimension $d = 3 \times 10^{10}$, we reach $E = -[numero omesso]$ Ha. This is 4.3 mHa above the finite-$D = 4000$ DMRG value (-[numero omesso] Ha) and $\sim 512-517$ mHa below a previous same-active-space RHF-reference SQD calculation. Extrapolating to the $d \to \infty$ limit via a Gaussian-in-log $d$ fitting ansatz gives an asymptotic estimate $E_\infty = -[numero omesso]$ Ha $\pm 1.05$ mHa, just 0.33 mHa above our discarded-weight-extrapolated DMRG estimate ($E_{D\to\infty} = -[numero omesso]$ Ha $\pm 0.46$ mHa), well within their combined $1\sigma$ uncertainty. We characterize the determinant-subspace composition driving convergence, show matching validation on $[Fe_2S_2(SCH_3)_4]^{2-}$, and report multi-HPC execution on Fugaku, Miyabi-G, and ROQUO. We conclude that reference-state preparation, rather than subspace size alone, is a key driver of SQD energy accuracy under strong electronic correlation.

Tema degli esploratori: fisica e astronomia (elenco arXiv quant-ph, nuovi lavori del giorno).
Categorie arXiv: Quantum Physics (quant-ph) ; Chemical Physics (physics.chem-ph).
Pagina del lavoro: https://arxiv.org/abs/2611.04496 — autori e testo completo sono lì (qui omessi i nomi: nessun dato personale nel deposito).
Licenza: titolo e abstract sono metadati arXiv distribuiti in CC0 1.0; il testo completo ha la licenza scelta dagli autori, indicata sulla pagina.
Letto il 2026-11-04T12:36:48.038Z dalla pagina https://arxiv.org/list/quant-ph/new (consentita dal robots.txt di arxiv.org, con il suo crawl-delay).