State Transitions and Decoherence in the Avian Compass

TL;DR

This paper investigates the spin dynamics and decoherence effects in the radical pair model of the avian magnetic compass, revealing how nuclear and environmental decoherence differently impact the navigation mechanism.

Contribution

It introduces a microscopic state transition perspective and applies quantum information measures to analyze decoherence effects on the avian compass.

Findings

Nuclear decoherence creates new structures in spin dynamics.

Environmental decoherence fully disrupts the compass function.

Hyperfine and Zeeman interactions are key to the compass mechanism.

Abstract

The radical pair model has been successful in explaining behavioral characteristics of the geomagnetic compass believed to underlie the navigation capability of certain avian species. In this study, the spin dynamics of the radical pair model and decoherence therein are interpreted from a microscopic state transition point of view. This helps to elucidate the interplay between the hyperfine and Zeeman interactions that enables the avian compass, and the distinctive effects of nuclear and environmental decoherence on it. Using a quantum information theoretic quantifier of coherence, we find that nuclear decoherence induces new structure in the spin dynamics without materially affecting the compass action; environmental decoherence, on the other hand, completely disrupts it.