Radical Pairs

A radical pair is described as paired quantum particles whose states become entangled. Radical pairs are described as reactive particles whose spin states can be influenced by magnetic fields. The article suggests human cells may have similar magnetic-field-sensitive processes but does not establish they work like bird navigation. Entangled radical-pair particles are described as having linked information even when separated. The proposed bird magnetoreception mechanism begins when photons enter the eye and form radical pairs. Birds are described as using photons, radical-pair formation, and Earth’s magnetic field for navigation. Bird navigation is used as a concrete example of radical-pair-based quantum sensing.