Suter, DieterMueller, K. T.Pines, A.2008-02-112008-02-111988-03D. Suter, K.T. Mueller, and A. Pines: Study of the Aharonov-Anandan Phase by NMR Interferometry. In: Phys. Rev. Lett. 60, pp 1218-1220 (1988).http://hdl.handle.net/2003/2499910.17877/DE290R-3226Aharonov and Anandan have recently reformulated and generalized Berry’s phase by showing that a quantum system which evolves through a circuit C in projective Hilbert space acquires a geometrical phase β(C) related to the topology of the space and the geometry of the circuit. We present NMR interferometry experiments in a three-level system which demonstrate the Aharonov-Anandan phase and its topological invariance for different circuits.enThe American Physical Society53010.1103/PhysRevLett.60.1218article (journal)http://prola.aps.org/abstract/PRL/v60/i13/p1218_1