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DOE OSTI · 1816720

Creating heralded hyper-entangled photons using Rydberg atoms

Ghosh, Sutapa·Rivera, Nicholas·Eisenstein, Gadi·Kaminer, Ido
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Abstract

Entangled photon pairs are a fundamental component for testing the foundations of quantum mechanics, and for modern quantum technologies such as teleportation and secured communication. Current state-of-the-art sources are based on nonlinear processes that are limited in their efficiency and wavelength tunability. This motivates the exploration of physical mechanisms for entangled photon generation, with a special interest in mechanisms that can be heralded, preferably at telecommunications wavelengths. Here we present a mechanism for the generation of heralded entangled photons from Rydberg atom cavity quantum electrodynamics (cavity QED). We propose a scheme to demonstrate the mechanism and quantify its expected performance. The heralding of the process enables non-destructive detection of the photon pairs. The entangled photons are produced by exciting a rubidium atom to a Rydberg state, from where the atom decays via two-photon emission (TPE). A Rydberg blockade helps to excite a single Rydberg excitation while the input light field is more efficiently collectively absorbed by all the atoms. The TPE rate is significantly enhanced by a designed photonic cavity, whose many resonances also translate into high-dimensional entanglement. The resulting high-dimensionally entangled photons are entangled in more than one degree of freedom: in all of their spectral components, in addition to the polarization—forming a hyper-entangled state, which is particularly interesting in high information capacity quantum communication. We characterize the photon comb states by analyzing the Hong-Ou-Mandel interference and propose proof-of-concept experiments.

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74 ATOMIC AND MOLECULAR PHYSICSatom opticsquantum optics

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Ghosh, Sutapa, Rivera, Nicholas, Eisenstein, Gadi, Kaminer, Ido. 2021-05-12. Creating heralded hyper-entangled photons using Rydberg atoms. https://doi.org/10.1038/s41377-021-00537-2

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