We demonstrate quantum entanglement of two trapped atomic ion qubits using a sequence of ultrafast laser pulses. Unlike previous demonstrations of entanglement mediated by the Coulomb interaction, this scheme does not require confinement to the Lamb-Dicke regime and can be less sensitive to ambient noise due to its speed. To elucidate the physics of an ultrafast phase gate, we generate a high entanglement rate using just 10 pulses, each of ∼20 ps duration, and demonstrate an entangled Bell-state with (76±1)% fidelity. These results pave the way for entanglement operations within a large collection of qubits by exciting only local modes of motion.
@article{arxiv.1709.05179,
title = {Demonstration of two-atom entanglement with ultrafast optical pulses},
author = {J. D. Wong-Campos and S. A. Moses and K. G. Johnson and C. Monroe},
journal= {arXiv preprint arXiv:1709.05179},
year = {2017}
}