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Distribución de entrelazamiento anunciada entre dos memorias cuánticas absorbentes
Xiao Liu1,2, Jun Hu1,2, Zong-Feng Li1,2
1CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, China.
Nature
|June 3, 2021
Resumen
Los investigadores demostraron la distribución anunciada del entrelazamiento entre las memorias cuánticas absorbentes, un paso crucial para construir repetidores cuánticos prácticos. Este avance supera las limitaciones de los métodos anteriores, allanando el camino para las redes cuánticas de alta velocidad.
Área de la Ciencia:
- Ciencia de la información cuántica
- La comunicación cuántica
Sus antecedentes:
- La distribución del entrelazamiento está limitada por la pérdida de canal, lo que restringe la comunicación terrestre a ~ 100 km.
- Se proponen repetidores cuánticos, utilizando memoria cuántica y intercambio de entrelazamiento, para superar las limitaciones de distancia.
- Los enlaces elementales de repetidores cuánticos existentes utilizan memorias cuánticas incorporadas, enfrentando compensaciones entre la multiplexación y el determinismo.
Objetivo del estudio:
- Para demostrar experimentalmente la distribución del entrelazamiento anunciado entre las memorias cuánticas absorbentes.
- Para superar las limitaciones de las memorias cuánticas incorporadas en los enlaces elementales del repetidor cuántico.
- Permitir el desarrollo de repetidores cuánticos eficientes y prácticos.
Principales métodos:
- Construido dos nodos cuánticos, cada uno con una fuente de pares de fotones entrelazados por polarización y una memoria cuántica absorbente de estado sólido (ancho de banda de 1 GHz).
- Separamos los nodos por 3,5 metros.
- Realizó una medición conjunta del estado de Bell en una estación intermedia para anunciar la distribución del entrelazamiento.
Principales resultados:
- Se logró con éxito la distribución de entrelazamiento anunciada entre las dos memorias cuánticas absorbentes remotas.
- Se alcanzó una fidelidad de 80,4 ± 2,2% para los estados entrelazados distribuidos.
- Demostró un enlace funcional elemental para un repetidor cuántico.
Conclusiones:
- El sistema demostrado, utilizando memorias cuánticas absorbentes, supera las limitaciones de los enfoques anteriores.
- Las memorias cuánticas absorbentes de banda ancha son compatibles con las fuentes de entrelazamiento determinista y admiten la multiplexación.
- Este trabajo allana el camino para repetidores cuánticos de estado sólido prácticos y redes cuánticas de alta velocidad.
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