Pith Number

pith:YO3BP77V

pith:2025:YO3BP77VCJUBODGBCBF3OA4KQ4

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Ensemble Inequivalence in Long-Range Quantum Spin Systems

Daniel Arrufat-Vicente, David Mukamel, Nicolo Defenu, Stefano Ruffo

Microcanonical and canonical ensembles produce different phase diagrams for long-range quantum ferromagnets at finite temperatures.

arxiv:2504.14008 v2 · 2025-04-18 · cond-mat.stat-mech

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Record completeness

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4 Citations open

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The bundle contains the canonical record plus signed events. A mirror can host it anywhere and recompute the same current state with the deterministic merge algorithm.

Claims

C1strongest claim

At finite temperatures the microcanonical and canonical ensembles yield different phase diagrams for the long-range quantum ferromagnet.

C2weakest assumption

The specific long-range quantum ferromagnet spin model chosen for the analysis is representative of the general class of long-range quantum systems that exhibit ensemble inequivalence.

C3one line summary

A long-range quantum ferromagnet exhibits ensemble inequivalence, with microcanonical and canonical phase diagrams agreeing at T=0 but diverging at finite temperatures.

References

79 extracted · 79 resolved · 0 Pith anchors

[1] and f(mz = m∗ z) are both global minima of the free energy, i.e. f(mz = 0) = f(m∗ z) , ∂mz f(mz) mz=0 = ∂mz f(mz) mz=m∗z = 0 , (33) yielding the following conditions m∗ z = tanh β p h2 + (2J m∗z + 4Km

[2] , J m∗ z 2 + 3Km ∗ z 4 + 1 β ln (coshβh) = 1 β ln cosh β q h2 + 2J m∗ + 4Km ∗3 2 , (34) whose solution is found numerically and reported in Fig. 1. 5 B. Microcanonical ensemble. To determine the secon

[3] = 0 , h2m∗ z 2 + (ε + J m∗ z 2 + Km ∗ z 4)2 = ε2 . (46) The first equation expresses the requirement that the so- lution mz = ±m∗ z is a local extremum of the entropy, while the second equation result

[4] Colloquium: Trapping and manipulating photon states in atomic ensembles, 2003

[5] Quantum information with Rydberg atoms, 2010

Receipt and verification

First computed	2026-06-02T03:05:03.481840Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

c3b617fff51268170cc1104bb7038a870555d37c7d3743faac264f0c4f294701

Aliases

arxiv: 2504.14008 · arxiv_version: 2504.14008v2 · doi: 10.48550/arxiv.2504.14008 · pith_short_12: YO3BP77VCJUB · pith_short_16: YO3BP77VCJUBODGB · pith_short_8: YO3BP77V

Agent API

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Verify this Pith Number yourself

curl -sH 'Accept: application/ld+json' https://pith.science/pith/YO3BP77VCJUBODGBCBF3OA4KQ4 \
  | jq -c '.canonical_record' \
  | python3 -c "import sys,json,hashlib; b=json.dumps(json.loads(sys.stdin.read()), sort_keys=True, separators=(',',':'), ensure_ascii=False).encode(); print(hashlib.sha256(b).hexdigest())"
# expect: c3b617fff51268170cc1104bb7038a870555d37c7d3743faac264f0c4f294701

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "24539804a78d8831f2e7b8efdb9f87931ea0337183784e70525f18fb6769c914",
    "cross_cats_sorted": [],
    "license": "http://creativecommons.org/licenses/by-nc-nd/4.0/",
    "primary_cat": "cond-mat.stat-mech",
    "submitted_at": "2025-04-18T18:01:26Z",
    "title_canon_sha256": "6cd68217373a7a0cbf833f58916d047d623baa08222c24fbd4a4479abc7edc2e"
  },
  "schema_version": "1.0",
  "source": {
    "id": "2504.14008",
    "kind": "arxiv",
    "version": 2
  }
}