Should recombinations of radical pairs be considered as accompanied by measurements?

TL;DR

This paper defends the phenomenological kinetic equation for spin-selective reactions, deriving it from a bosonic pair density operator framework and discussing issues with measurement-based approaches.

Contribution

It provides a derivation of the phenomenological kinetic equation from a bosonic pair perspective and critiques measurement-based interpretations.

Findings

Derivation of the kinetic equation from pair density operators.

Identification of inconsistencies in measurement-like approaches.

Arguments supporting the phenomenological model's validity.

Abstract

The so-called "phenomenological" kinetic equation for one-pair density operator for spin-selective reactions is defended. We derive this equation from the kinetic equation for density operator of all pairs which are treated as singlet and triplet bosons. There presented some reasons for inconsistency of measurement-like approach to the problem.