arXiv subjects

J. Enrique Vázquez-Lozano

Publications and source records attributed to J. Enrique Vázquez-Lozano.

20 records · Page 2Linked to original sources

arXiv2016

Effective geometric phases and topological transitions in SO(3) and SU(2) rotations

We address the development of geometric phases in classical and quantum magnetic moments (spin-1/2) precessing in an external magnetic field. We show that nonadiabatic dynamics lead to a topological phase transition determined by a change in the driving field topology. The transition is associated with an effective geometric phase which is identified from the paths of the magnetic moments in a spherical geometry. The topological transition presents close similarities between SO(3) and SU(2) cases but features differences in, e.g., the adiabatic limits of the geometric phases, being $2π$ and $π$ in the classical and the quantum case, respectively. We discuss possible experiments where the effective geometric phase would be observable.

cond-mat.mes-hall↗

arXiv2015

Topological transitions in spin interferometers

We show that topological transitions in electronic spin transport are feasible by a controlled manipulation of spin-guiding fields. The transitions are determined by the topology of the fields texture through an effective Berry phase (related to the winding parity of spin modes around poles in the Bloch sphere), irrespective of the actual complexity of the nonadiabatic spin dynamics. This manifests as a distinct dislocation of the interference pattern in the quantum conductance of mesoscopic loops. The phenomenon is robust against disorder, and can be experimentally exploited to determine the magnitude of inner spin-orbit fields.

cond-mat.mes-hall↗