Birds, Brains, and Quantum Biology: the Influence of Quantum Dynamics on Classical Biological Behavior

Abstract

This thesis explores the interplay between quantum physics and biological organization across two frontiers: Quantum Biology, where genuine quantum mechanical processes influence macroscopic life, and Quantum-Like systems, where classical systems exhibit mathematical structures formally resembling quantum mechanics. By investigating both domains, I aim to illuminate how quantum principles manifest both directly in biological function and indirectly through emergent organizational patterns. I begin by deriving a generalized Hamiltonian for the Radical Pair Mechanism underlying avian magnetoreception, capturing how hyperfine interactions and Zeeman interactions with the Earth’s magnetic field modulate singlet-triplet interconversion in cryptochrome proteins. Analytical and numerical treatments demonstrate how coherent spin dynamics can influence global navigation behavior, providing a tractable model for quantum biological sensing. Then, I traverse scales and investigate the emergence of Quantum-Like (QL) structures within the human brain. Drawing inspiration from modern whole-brain modeling techniques, particularly Connectome Harmonic Decomposition, I map real neurophysiological data onto QL graphs, constructing a framework where physical brain dynamics are represented by robust, scalable QL state spaces. Together, these investigations suggest that quantum mechanics may not only shape specialized biological functions, but also that classical systems like the brain can mirror quantum architectures, hinting at deeper symmetries between the fundamental and living worlds.