Timestamp proof

Status

Anchored in Bitcoin

Bitcoin block

#969,239

Block time

2026-09-30 02:33 UTC

Recorded

2026-09-30 01:04 UTC

SHA-256

81630ac02eaf898ac1cebb008d8711517ba72f9ccbc38b081c7b8ebc9c3be462

Verify it

1. Here, in one click

Checks the stored proof against the Bitcoin blockchain and confirms it covers the payload below. To check files you downloaded, use Verify a timestamp.

2. On opentimestamps.org (independent of PubPhys)

1. Download the payload (.json) and the proof (.ots) above.
2. Open opentimestamps.org and drop pubphys-problem-43-stamp-11.json.ots onto Drop here a file to stamp or an .ots proof file to verify in the Stamp & Verify section.
3. Then drop pubphys-problem-43-stamp-11.json onto Drop here the stamped file.
4. The site reports the Bitcoin block that attests the file — here block #969,239. Your file never leaves the browser; only its hash is compared.

3. From the command line

With both files in one folder, run the reference Python client (pip install opentimestamps-client) or the Ruby gem (gem install opentimestamps, 0.4 or newer):

ots verify pubphys-problem-43-stamp-11.json.ots

The Ruby gem checks the block against a public block explorer. The Python client checks it only against your own Bitcoin Core node; without one, run ots --no-bitcoin verify pubphys-problem-43-stamp-11.json.ots and compare the merkle root it prints with the block's merkle root on any explorer (e.g. block 969239).

Until the calendars anchor the proof in a Bitcoin block (usually a few hours), every check reports it as pending. Once PubPhys shows a block number, download the proof again, or complete your copy with ots upgrade pubphys-problem-43-stamp-11.json.ots.

Hashed payload

{
  "author": "emmy_noether",
  "field": "quantum_field_theory",
  "id": 43,
  "published_at": "2026-08-08T05:48:51Z",
  "recorded_at": "2026-09-30T01:04:42Z",
  "references": null,
  "schema": "physicdb.problem/1",
  "site": "physicdb.yet.bz",
  "slug": "the-strong-cp-problem",
  "statement": "QCD allows a CP-violating term\n$$\\mathcal{L}_\\theta = \\theta\\,\\frac{g^2}{32\\pi^2} G_{\\mu\\nu}^a \\tilde G^{a\\,\\mu\\nu},$$\nyet the neutron electric dipole moment forces $|\\theta| \\lesssim 10^{-10}$.\n\nWhy is $\\theta$ so unnaturally small? The Peccei–Quinn axion is the leading proposal, but the axion has not been detected.\n",
  "title": "The Strong CP Problem"
}

Shown pretty-printed; the digest covers the compact bytes in the downloadable file.