Pith Number

pith:KQGK2CAE

pith:2026:KQGK2CAEX3XKFSUE4BDEEM6KQC

not attested not anchored not stored refs pending

Degenerate coupled-cluster theory

So Hirata

A new coupled-cluster ansatz called ΔCC computes energies and wave functions from any degenerate or nondegenerate Slater-determinant reference while staying size-extensive and converging to full configuration interaction.

arxiv:2601.17163 v4 · 2026-01-23 · physics.chem-ph · cond-mat.str-el · nucl-th

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\pithnumber{KQGK2CAEX3XKFSUE4BDEEM6KQC}

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Record completeness

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2 Internet Archive

3 Author claim open · sign in to claim

4 Citations open

5 Replications 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

A size-extensive, converging, black-box, ab initio coupled-cluster (ΔCC) ansatz is introduced that computes the energies and wave functions of stationary states from any degenerate or nondegenerate Slater-determinant references with any numbers of α- and β-spin electrons, any patterns of orbital occupancy, any spin multiplicities, and any spatial symmetries.

C2weakest assumption

That the newly defined ΔCC ansatz is size-extensive and converges to the full-configuration-interaction limit for arbitrary references and that the slight modification yielding QCC preserves these properties without introducing uncontrolled approximations.

C3one line summary

A size-extensive, converging, black-box coupled-cluster ansatz (ΔCC) is introduced for arbitrary degenerate or nondegenerate references, reducing to standard CC when appropriate, with a related state-universal QCC variant developed for strong correlation.

Formal links

2 machine-checked theorem links

Receipt and verification

First computed	2026-05-17T23:39:00.169793Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

540cad0804beeea2ca84e0464233ca80bcf46dd9f593398d352e3f3acb9aaf7e

Aliases

arxiv: 2601.17163 · arxiv_version: 2601.17163v4 · doi: 10.48550/arxiv.2601.17163 · pith_short_12: KQGK2CAEX3XK · pith_short_16: KQGK2CAEX3XKFSUE · pith_short_8: KQGK2CAE

Agent API

Resolver JSON Graph JSON Events JSON Schema Signing key

Verify this Pith Number yourself

curl -sH 'Accept: application/ld+json' https://pith.science/pith/KQGK2CAEX3XKFSUE4BDEEM6KQC \
  | 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: 540cad0804beeea2ca84e0464233ca80bcf46dd9f593398d352e3f3acb9aaf7e

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "7eac815eca77293d057d4e24f218ac0abb5388e7559c646e360eacba136664d4",
    "cross_cats_sorted": [
      "cond-mat.str-el",
      "nucl-th"
    ],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "primary_cat": "physics.chem-ph",
    "submitted_at": "2026-01-23T20:49:00Z",
    "title_canon_sha256": "fc5334df801a7ce2703a6dc8cb517cc5cde8b69d8990f2bfa3279ae14dde43e4"
  },
  "schema_version": "1.0",
  "source": {
    "id": "2601.17163",
    "kind": "arxiv",
    "version": 4
  }
}