Proceedings Article | 28 May 2014
Proc. SPIE. 9123, Quantum Information and Computation XII
KEYWORDS: Semiconductors, Light sources, Polarization, Chemical species, Photons, Magnetism, Quantum dots, Optical testing, Excitons, Electroluminescent displays
Compared to classical light sources, quantum sources based on N00N states consisting of <i>N</i> photons achieve an <i>N</i>-times higher phase sensitivity, giving rise to super-resolution.<sup>1, 2, 3</sup> N00N-state creation schemes based on linear optics and projective measurements only have a success probability <i>p</i> that decreases exponentially with N,<i>4, 5, 6</i> e.g. p = 4.4x10<sup>-14 </sup>for <i>N</i> = 20.<sup>7</sup> Feed-forward improves the scaling but<i> N </i>fluctuates nondeterministically in each attempt.<sup>8, 9</sup> Schemes based on parametric down-conversion suffer from low production efficiency and low fidelity.<sup>9</sup> A recent scheme based on atoms in a cavity combines deterministic time evolution, local unitary operations, and projective measurements.<sup>10</sup> Here we propose a novel scheme based on the off-resonant interaction of <i>N</i> photons with four semiconductor quantum dots (QDs) in a cavity to create GHZ states, also called polarization N00N states, deterministically with<i> p</i> = 1 and fidelity above 90% for N≤ 60, without the need of any projective
measurement or local unitary operation. Using our measure we obtain maximum N-photon entanglement E<sub>N</sub> = 1 for arbitrary <i>N</i>. Our method paves the way to the miniaturization of N00N and GHZ-state sources to the nanoscale regime, with the possibility to integrate them on a computer chip based on semiconductor materials.
