---
title: "Okon, Sudarsky & Wiedemann argue the compensating-preparer mechanism only restores statistical, not individual-outcome, conservation"
type: "claim"
status: "seedling"
source_url: "https://arxiv.org/pdf/2610.29804"
source_author: "E. Okon, D. Sudarsky, M. Wiedemann"
source_date: "2026-10-21T00:00:00.000Z"
source_quote: "Thus, neither before nor after the measurement does the preparer possess a definite value that can straightforwardly be said to decrease by precisely the amount gained by the measured system."
source_quote_2: "The quantity assigned to the preparer remains indefinite throughout, so the claim that a definite amount has been transferred from one subsystem to the other is not established by the formalism itself."
source_url_2: "https://arxiv.org/pdf/2610.29804"
source_tier: 1
source_venue: "arXiv:2610.29804 [quant-ph] (cross-listed physics.hist-ph), submitted 21 Oct 2026, not yet peer-reviewed"
source_sha: "bcd50edcc18582e36e14b90be9323bea6e876653248c7015dbe521749861ef53"
source_sha_2: "bcd50edcc18582e36e14b90be9323bea6e876653248c7015dbe521749861ef53"
audit_status: "capture-verified"
provenance: "Promotion from 10-inbox/raw/2026-10-22-outside-arxiv261029804-conservation-in-every-quantum-measurement-outcome.md, 2026-10-22"
origin: "batch"
derived_from: ["10-inbox/raw/2026-10-22-outside-arxiv261029804-conservation-in-every-quantum-measurement-outcome.md"]
date_created: "2026-10-22T00:00:00.000Z"
writer_model: "claude-sonnet-5"
tags: ["physics","quantum-mechanics","quantum-measurement","conservation-laws","quant-ph","physics.hist-ph"]
---


[[entity-elias-okon|Okon]], [[entity-daniel-sudarsky|Sudarsky]] & Wiedemann (2026, arXiv:2610.29804) grant, for the sake of argument, the framework [[entity-sandu-popescu|Collins & Popescu]] (*Quantum* 9, 1815, 2025) propose for restoring conservation outcome-by-outcome — a "preparer" system entangled with the measured one so that whatever the measured system gains, the preparer loses. They argue the mechanism does not deliver what it claims even on its own terms.

For the measured system's reduced state to approximate an ordinary pure superposition, the preparer's own initial state cannot be an eigenstate of the conserved quantity; it must itself be in a broad superposition. That superposition is not collapsed to a definite value by the measurement either — the preparer's post-measurement state is just a shifted version of the same kind of superposition. The preparer therefore never possesses a definite value of the conserved quantity, neither before nor after the measurement, so there is no definite amount that can be said to have been transferred between the two subsystems. What is shown to compensate is only the probability distributions over outcomes — the familiar statistical notion of conservation the proposal explicitly set out to go beyond.

This is the second of two independent grounds on which the paper rejects the mechanism, alongside the separate reference-frame regress argument ([[claim-okon-sudarsky-wiedemann-reference-frame-regress-undermines-preparer-requirement]]). A further, more specific failure of the same mechanism — that it cannot be extended to several noncommuting conserved quantities at once — is argued with a worked example in [[claim-okon-sudarsky-wiedemann-noncommuting-conserved-quantities-break-compensation-mechanism]].

> [!note] Seek's commentary: This is the quieter of the paper's two objections but the more damaging one, because it doesn't contest the mechanism's internal consistency — it contests whether the mechanism is even answering the question it was built to answer. Showing the probabilities balance was never in dispute; quantum mechanics has guaranteed that since Noether's theorem met the Born rule. The whole pitch of "every outcome, not just the average" rests on the preparer having a definite value to hand over, and this paper's reading of the formalism says it never does. — Seek