Pith Number

pith:VVFGDQ2U

pith:2003:VVFGDQ2UE46XUOCHD4JIIH367I

not attested not anchored not stored refs pending

Maxwell's field coupled nonminimally to quadratic torsion: Induced axion field and birefringence of the vacuum

Friedrich W. Hehl, Yakov Itin

arxiv:gr-qc/0307063 v2 · 2003-07-13 · gr-qc

Open paper page JSON Open Graph Bundle Merged state Verified badge What is a Pith Number?

Add to your LaTeX paper

\usepackage{pith}
\pithnumber{VVFGDQ2UE46XUOCHD4JIIH367I}

Prints a linked badge after your title and injects PDF metadata. Compiles on arXiv. Learn more · Embed verified badge

Record completeness

1 Bitcoin timestamp

2 Internet Archive

3 Author claim open · sign in to claim

4 Citations open

5 Replications open

✓ Portable graph bundle live · download bundle · merged state

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.

Receipt and verification

First computed	2026-07-04T16:40:15.018864Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

ad4a61c354273d7a38471f12841f7efa2aa3bbbb6b5e6d8a780fd9ce3a189cc5

Aliases

arxiv: gr-qc/0307063 · arxiv_version: gr-qc/0307063v2 · doi: 10.48550/arxiv.gr-qc/0307063 · pith_short_12: VVFGDQ2UE46X · pith_short_16: VVFGDQ2UE46XUOCH · pith_short_8: VVFGDQ2U

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/VVFGDQ2UE46XUOCHD4JIIH367I \
  | 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: ad4a61c354273d7a38471f12841f7efa2aa3bbbb6b5e6d8a780fd9ce3a189cc5

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "abe812bef8d4986804700424e7251eb0e7f16725420a2d7fe555f7d05ed6d544",
    "cross_cats_sorted": [],
    "license": "",
    "primary_cat": "gr-qc",
    "submitted_at": "2003-07-13T08:48:43Z",
    "title_canon_sha256": "244b6caf7567bd11e241cf0f8b2cd08e8355a18195c7ff17d13e4ab3271c58ce"
  },
  "schema_version": "1.0",
  "source": {
    "id": "gr-qc/0307063",
    "kind": "arxiv",
    "version": 2
  }
}