arXiv:1608.03076 · Physical Review Letters
Hong-Ou-Mandel Interference between Two Deterministic Collective Excitations in an Atomic Ensemble
Jun Li, Ming-Ti Zhou, Bo Jing, Xu-Jie Wang, Sheng-Jun Yang, Xiao Qiang Jiang, Klaus Mølmer, Xiao‐Hui Bao, Jian-Wei Pan
Abstract
We demonstrate deterministic generation of two distinct collective excitations in one atomic ensemble, and we realize the Hong-Ou-Mandel interference between them. Using Rydberg blockade we create single collective excitations in two different Zeeman levels, and we use stimulated Raman transitions to perform a beam-splitter operation between the excited atomic modes. By converting the atomic excitations into photons, the two-excitation interference is measured by photon coincidence detection with a visibility of 0.89(6). The Hong-Ou-Mandel interference witnesses an entangled NOON state of the collective atomic excitations, and we demonstrate its two times enhanced sensitivity to a magnetic field compared with a single excitation. Our work implements a minimal instance of boson sampling and paves the way for further multimode and multiexcitation studies with collective excitations of atomic ensembles.