Javier Gómez,1,2 Antonio Peimbert,2 and Juan Echevarría2
1 The Citadel, Department of Physics, 172 Moultrie St., Charleston, SC, USA. (javier.gomez@citadel.edu).
2 Instituto de Astronomía, Universidad Nacional Autónoma de México, Apdo. Postal 70-264, 04510 México, D. F., México. (jer@astroscu.unam.mx, antonio@astroscu.unam.mx).
Received 2009 June 2
Accepted 2009 July 24
]]> RESUMEN
Las teorías del entrelazamiento cuántico entre dos partículas lejanas, que claramente confirman la naturaleza no local de la Mecánica Cuántica, se aplican a las partículas producidas naturalmente en los objetos astrofísicos. Estudiamos la producción y la recepción del caso de entrelazamiento cuántico más factible de observarse: la transición espontánea de dos–fotones del nivel metastable 2 2S1/2 del hidrógeno, componente conocido del espectro del continuo de las regiones ionizadas. Obtenemos la tasa de emisión de dos–fotones para cuatro objetos astrofísicos: la Nebulosa de Orion, dos nebulosas planetarias cercanas IC 2149 y NGC 7293, y la corona solar. La producción de pares entrelazados por segundo es de 5.80 × 1048, 9.39 × 1045, 9.77 × 1044 y 1.46 × 1016, respectivamente. La distribución de las direcciones de propagación de ambos fotones emitidos no se anula para ningún ángulo; por lo que es posible observar el par entrelazado a ángulos θ ≈ 0°. Debido a que el número de coincidencias de dos–fotones va como el cociente entre el tamaño del detector y la distancia al objeto astrofísico elevado a la cuarta potencia, las coincidencias son escasas; para su detección se requiere de receptores de un tamaño mucho mayor que los que existen en la actualidad.
ABSTRACT
The theories of quantum entanglement between two distant particles, which clearly confirm the non–local nature of Quantum Mechanics, are applied to naturally produced particles in astrophysical objects. We study the production and reception of the cases of optical quantum entanglement most feasible to be observed: the two–photon spontaneous transition of the hydrogen 2 2S1/2 metastable level, which is known to be one of the components of the continuous spectra of ionized regions. We obtain the two–photon emission rate for four astrophysical objects: the Orion Nebula, two nearby planetary nebulae IC 2149 and NGC 7293, and the solar corona. The production of entangled pairs per second is 5.80 × 1048, 9.39 × 1045, 9.77 × 1044, and 1.46 × 1016 respectively. The distribution of the propagation directions of both emitted photons does not vanish at any angle; therefore it is possible to observe the entangled pair at angles θ ≈ 0°. Because the number of two–photon coincidences goes as the fourth power of the ratio between the detector size and the distance from the astrophysical object, coincidences are scarce; for its detection we require receivers much larger than those currently available.
Key Words: HII regions — planetary nebulae: individual (IC 2149, NGC 7293) — Sun: corona.
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