Reply to "Masanes-Galley-M\"uller and the State-Update Postulate"

TL;DR

This paper defends a previous derivation of the quantum state update rule against criticism, clarifying that their proof does not rely on linearity assumptions, thus strengthening their original argument.

Contribution

The authors refute the criticism by clarifying that their derivation of the quantum state update rule does not depend on linearity assumptions, reinforcing their original proof.

Findings

Their proof of the quantum state update rule does not assume linearity.

The criticism claiming linearity assumption is unfounded.

The original derivation remains valid despite the critique.

Abstract

In a recent comment on the arXiv, Blake C. Stacey criticizes our derivation of the quantum state update rule in Nat. Commun. 10, 1361 (2019). Here we argue that the criticism is unfounded. In particular, and in contrast to Stacey's claims, our proof does not assume linearity.