Securing coherence rephasing with a pair of adiabatic rapid passages

• Autores: Pascual Winter, María Florencia; Tongning, R. C.; Chanelière, T.; Le Gouët, J. L.
• Año de publicación: 2013
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: ADIABATIC RAPID PASSAGES; RARE-EARTH ION DOPED CRYSTALS; QUANTUM MEMORIES
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

Coherence rephasing is an essential step in quantum storage protocols that use echo-based strategies. We present a thorough analysis on how two adiabatic rapid passages (ARPs) are able to rephase atomic coherences in an inhomogeneously broadened ensemble. We consider both optical and spin coherences, rephased by optical or radio-frequency (rf) ARPs, respectively. We show how a rephasing sequence consisting of two ARPs in a double-echo scheme is equivalent to the identity operator (any state can be recovered), as long as certain conditions are fulfilled. Our mathematical treatment of the ARPs leads to a very simple geometrical interpretation within the Bloch sphere that permits a visual comprehension of the rephasing process. We also identify the conditions that ensure the rephasing, finding that the phase of the optical or rf ARP fields plays a key role in the ability of the sequence to preserve the phase of the superposition state. This settles a difference between optical and rf ARPs, since field phase control is not readily guaranteed in the former case. We also provide a quantitative comparison between π-pulse and ARP rephasing efficiencies, showing the superiority of the latter. We experimentally verify the conclusions of our analysis through rf ARP rephasing sequences performed on the rare-earth ion-doped crystal Tm3+:YAG, of interest in quantum memories.
Fil: Pascual Winter, María Florencia. Universite Paris Sud; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Tongning, R. C.. Universite Paris Sud; Francia
Fil: Chanelière, T.. Universite Paris Sud; Francia
Fil: Le Gouët, J. L.. Universite Paris Sud; Francia