Quantum Theory of Exciton Magnetic Moment: Interaction and Topological Effects
The authors developed a quantum theory using GW plus Bethe-Salpeter Equation to explain exciton orbital magnetic moments in biased bilayer graphene. They found three key contributions—single-particle moment differences, envelope function winding, and center-of-mass quantum geometry—which together accurately predict experimental results for valley g-factors, proving the importance of electron-hole interactions and quantum geometric effects.