Estimating the HF coupling parameters of the avian compass by comprehensively considering the available experimental results

TL;DR

This study estimates hyperfine coupling parameters in the avian magnetic compass model by integrating experimental results, analyzing decoherence effects, and exploring magnetic noise impacts to better understand bird navigation mechanisms.

Contribution

It introduces a comprehensive approach considering experimental data, decoherence, and magnetic noise to refine the radical-pair model of avian magnetoreception.

Findings

Optimal hyperfine parameters are around 10^{-7} to 10^{-6} meV.

Decoherence rates must be much lower than recombination rates.

Vertical noise destroys monotonicity, while parallel noise can enhance direction sensitivity.

Abstract

Migratory birds can utilize the geomagnetic field for orientation and navigation through a widely accepted radical-pair mechanism. Although many theoretical works have been done the available experimental results have not been fully considered, especially, the temporary disorientation induced by the field which is increased by 30% of geomagnetic field and the disorientation of the very weak resonant field of $15nT$. In this paper, we consider the monotonicity of the singlet yield angular profile as the prerequisite of direction sensitivity, and find that for some optimal values of the hyperfine coupling parameters, that is the order of $10^{-7}\sim10^{-6}meV$, the experimental results available by far can be satisfied. We also investigate the effects of two decoherence environments and demonstrate that, in order to satisfy the available experimental results, the decoherence rate should be much lower than the recombination rate. Finally we investigate the effects of the fluctuating magnetic noises, and find that the vertical noise destroys the monotonicity of the profile completely, but the parallel noise preserves the monotonicity perfectly and even can enhance the direction sensitivity.