Finite-size spin fluctuations and fixed-index sweeps in a ferromagnetic spinor condensate

We find a dip in the optimized rotation quantum Fisher information of a zero-magnetization ferromagnetic spin-1 Bose-Einstein condensate near the excited-state quantum phase transition.

By Ding, Luo, HuangOct 20, 2026

Score████░░░░░░4.3

Key numbers

13.1 times their ground-state counterparts

Caveats

Preprint; not yet peer reviewed.

VerdictWorth a reader's time today.

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Abstract

We find a dip in the optimized rotation quantum Fisher information of a zero-magnetization ferromagnetic spin-1 Bose-Einstein condensate near the excited-state quantum phase transition. Its displacement from ε_c=-q decreases on an inverse-size scale. At q=0.6,0.8,1.0,1.2, the dip value of F_max equals 2langle S²rangle for N up to $3840$, linking it to total-spin fluctuations. A semiclassical orbit average normalized by the classical density of states describes the dip over N=120--$3840$ with maximum relative residual below $0.028$; a small power law fits comparably. Inserting the measured energy offsets directly into the semiclassical formula leaves residuals of $17$--30%, so $κ$ acts as an effective cutoff. Among retained states, spin-nematic squeezing occurs at the spectral edges. Separately, fixed-index excited-state sweeps have half-excitation times between $11.2$ and $13.1$ times their ground-state counterparts, with local size exponents increasing across the four sizes.

Yi Ding, Junyan Luo, Yixiao Huang

The editor's rubric

Heuristic review

Leverage3 / 5: A method or resource many groups across the field will adopt within a year.; 18% of this desk’s rubric
Magnitude3 / 5: Large gain: roughly 2x, or a clear new state of the art on a hard, unsaturated problem.; 20% of this desk’s rubric
Evidence3 / 5: Solid: multiple benchmarks or cohorts, ablations, fair baselines, released code or data.; 22% of this desk’s rubric
Novelty2 / 5: A new combination of known ideas.; 22% of this desk’s rubric
Trajectory3 / 5: A clear path to scale.; 10% of this desk’s rubric
Stakes2 / 5: Benefits a professional community (practitioners, clinicians, engineers).; 8% of this desk’s rubric

Dimension	Level	Weight	What that level means
Leverage	███░░ 3	18%	A method or resource many groups across the field will adopt within a year.
Magnitude	███░░ 3	20%	Large gain: roughly 2x, or a clear new state of the art on a hard, unsaturated problem.
Evidence	███░░ 3	22%	Solid: multiple benchmarks or cohorts, ablations, fair baselines, released code or data.
Novelty	██░░░ 2	22%	A new combination of known ideas.
Trajectory	███░░ 3	10%	A clear path to scale.
Stakes	██░░░ 2	8%	Benefits a professional community (practitioners, clinicians, engineers).

Editor’s rationale

Heuristic triage from title and abstract text only, not a reading of the paper. Cues found: method (we report); gains (x-fold); scale (scalable, power law); stakes (energy).

How the score was computed

rank-2026-10-18

Score████░░░░░░4.3

Score = 10 × (75% × adjusted merit / 10 + 15% × attention + 10% × freshness)

Desks place stronger verdicts first, then use this score to order work within the same verdict.

Merit: 5.4 / 10; Weighted rubric, evidence-gated.
Adjusted merit: 4.6 / 10; Shrunk toward the desk prior by editor confidence (40%).
Attention: 0%; Citations, upvotes, points, mentions.
Freshness: 93%; Half-life decay since publication.

No attention signals recorded yet.

The record

Reviewed by heuristic-v7 on Oct 21, 2026, 07:29 UTC. Paper type: method.
Categories: cond-mat.quant-gas
TOP, No.6 in the Physics edition of October 21, 2026.