Multi-Radical Lipkin-Meshkov-Glick Model for Avian Navigation

TL;DR

This paper models avian navigation using a radical pair coupled with an LMG bath, revealing quantum phase transition effects and invariant subspaces that could inform artificial navigation system design.

Contribution

It introduces a multi-radical Lipkin-Meshkov-Glick model to analyze quantum effects in avian navigation, highlighting phase transition impacts and computational simplifications.

Findings

Navigation ability weakest at quantum phase transition point

Invariant subspace identified when magnetic field is vertical to the plane

Results suggest quantum effects influence avian navigation mechanisms

Abstract

The mechanism of avian navigation is an important question for global scientists. One of the most famous candidates is the radical pair mechanism (RPM), which shows that avian navigation is achieved by detecting the amount of products from chemical reactions, which exhibit different properties for singlet and triplet spin states. Based on the theory, we explore the amount of the the singlet recombination product by changing the coupling strength and direction of the magnetic field. The radical pair in our model is coupled with a Lipkin-Meshkov-Glick (LMG) bath, which proposes attractive results at quantum phase transition (QPT) point, especially when the magnetic field is parallel with the original direction of the pair. We find weakest navigation ability in QPT point according to one of our proposing methods. And we find invariant subspace in our Hamiltonian when the magnetic field is vertical to the plane of the radical pair and the bath, which will greatly speed up our calculation. Our results could help the exploration of the design principle of artificial avian navigation.