Nonadiabatic coherent evolution of two-level systems under spontaneous decay.
In this Letter we extend current perspectives in engineering reservoirs by producing a time-dependent master equation leading to a nonstationary superposition equilibrium state that can be nonadiabatically controlled by the system-reservoir parameters. Working with an ion trapped inside a nonideal cavity, we first engineer effective interactions, which allow us to achieve two classes of decoherence-free evolution of superpositions of the ground and excited ionic levels: those with a time-dependent azimuthal or polar angle. As an application, we generalize the purpose of an earlier study [Phys. Rev. Lett. 96, 150403 (2006)10.1103/PhysRevLett.96.150403], showing how to observe the geometric phases acquired by the protected nonstationary states even under nonadiabatic evolution.
Prado
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FO
Departamento de Física, Universidade Federal de São Carlos, P.O. Box 676, São Carlos, 13565-905, São Paulo, Brazil.
Duzzioni
E I
EI
Moussa
M H Y
MH
de Almeida
N G
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Villas-Bôas
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CJ