Radical-ion-pair reactions are the biochemical equivalent of the optical double slit experiment

TL;DR

This paper demonstrates that radical-ion-pair reactions function as a biochemical double slit interferometer, illustrating quantum coherence effects and deriving a master equation that describes the transition from coherence to decoherence.

Contribution

It introduces a novel analogy between radical-ion-pair reactions and the optical double slit experiment, providing a fundamental master equation for their quantum dynamics.

Findings

Quantum coherence effects are observable when 'which-path' information is limited.

The master equation describes the full range from incoherent to maximally coherent states.

Radical-ion-pair reactions serve as a natural biochemical platform for quantum measurement studies.

Abstract

Radical-ion-pair reactions were recently shown to represent a rich biophysical laboratory for the application of quantum measurement theory methods and concepts. We here show that radical-ion-pair reactions essentially form a non-linear biochemical double slit interferometer. Quantum coherence effects are visible when "which-path" information is limited, and the incoherent limit is approached when measurement-induced decoherence sets in. Based on this analogy with the optical double slit experiment we derive and elaborate on the fundamental master equation of spin-selective radical-ion-pair reactions that covers the continuous range from complete incoherence to maximum singlet-triplet coherence.