Pith Number

pith:C77VFE3T

pith:2026:C77VFE3T6EW6BA55QUKGD5UJYX

not attested not anchored not stored refs resolved

An algebra of proper observables at null infinity: Dirac brackets, Memory and Goldstone probes

Rodrigo Andrade e Silva, Simone Speziale

The conventional Goldstone mode at null infinity is not a proper observable, but an infinite family of Goldstone probes can measure it.

arxiv:2605.13804 v1 · 2026-05-13 · hep-th · gr-qc · math-ph · math.MP

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Claims

C1strongest claim

the conventional definition of the ``Goldstone mode'' adopted in the literature cannot be associated with a proper observable, but nevertheless there exists an infinite family of proper observables, which we call Goldstone probes, that are capable of measuring the Goldstone mode. We notice that there are no Goldstone probes constructed only out of the shear or the news.

C2weakest assumption

boundary conditions in time given by vanishing news and purely electric shear on the Ashtekar-Streubel phase space

C3one line summary

The algebra of proper observables at null infinity admits Goldstone probes that measure the memory mode, but none can be built from shear or news alone, and the Dirac brackets acquire non-local corrections.

References

58 extracted · 58 resolved · 12 Pith anchors

[1] Ashtekar,Asymptotic Quantization of the Gravitational Field, Phys 1981

[2] Ashtekar,Asymptotic quantization : based on 1984 Naples lectures / Abhay Ashtekar 1984

[3] BMS supertranslations and Weinberg’s soft graviton 22 theorem 2015 · arXiv:1401.7026

[4] Strominger,Lectures on the Infrared Structure of Gravity and Gauge Theory · arXiv:1703.05448

[5] Null infinity, the BMS group and infrared issues 2018 · arXiv:1808.07093

Receipt and verification

First computed	2026-05-18T02:44:15.471908Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

17ff529373f12de083bd851461f689c5e1bf683e51a509e61b64c9594fb09498

Aliases

arxiv: 2605.13804 · arxiv_version: 2605.13804v1 · doi: 10.48550/arxiv.2605.13804 · pith_short_12: C77VFE3T6EW6 · pith_short_16: C77VFE3T6EW6BA55 · pith_short_8: C77VFE3T

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Verify this Pith Number yourself

curl -sH 'Accept: application/ld+json' https://pith.science/pith/C77VFE3T6EW6BA55QUKGD5UJYX \
  | 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: 17ff529373f12de083bd851461f689c5e1bf683e51a509e61b64c9594fb09498

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "8607eddffcdab5fd0939207eda0d5cf1c785d837e29049214b123e8d53995548",
    "cross_cats_sorted": [
      "gr-qc",
      "math-ph",
      "math.MP"
    ],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "primary_cat": "hep-th",
    "submitted_at": "2026-05-13T17:29:39Z",
    "title_canon_sha256": "f38af9d973975167718618fdce056854508e42e962aa974549119fc58a3439c1"
  },
  "schema_version": "1.0",
  "source": {
    "id": "2605.13804",
    "kind": "arxiv",
    "version": 1
  }
}