With Seigert, this man names a frequency shift that occurs during the Rabi oscillation, and another 
With Seigert, this man names a frequency shift that occurs during the Rabi oscillation, and another construct named for this man employs the Fubini-Study metric and is used to model a two-level quantum system. A phenomenon named for him is the product of a plane wave envelope function and a periodic function. In addition to his namesake sphere, which is used to model qubits, and his namesake waves in crystalline systems, his theorem is used to model an electron placed in a periodic potential. His walls separate magnetic domains, and another set of equations named for him is used to model the relaxation time in a technique he co-developed. For 10 points, name this physicist, who, with Purcell, developed NMR.
With Seigert, this man names a frequency shift that occurs during the Rabi oscillation, and another construct named for this man employs the Fubini-Study metric and is used to model a two-level quantum system.
Felix Bloch