Colloquium featuring Lindsay LeBlanc

Quantum memory and manipulation with cold and ultracold atomic ensembles

Abstract
The ability to store and manipulate quantum information encoded in electromagnetic (often optical) signals represents one of the key tasks for quantum communications and computation schemes. In the pursuit of a practical but efficient and broadband quantum memory, we make use of a three-level atomic system (in our case, laser-cooled and Bose-condensed rubidium atoms) and realize storage and photonic manipulations in the regime of Autler-Townes splitting (ATS), where a classical-level control field controls the absorption of an auxillary, possibly quantum, signal field. We demonstrate on-demand storage and retrieval of both high-power and less-than-one-photon optical signals with total efficiencies up to 30%, using the ground state spin-wave as our storage states. We also realize a number of photonic manipulations, including temporal beamsplitting, frequency conversion, and pulse shaping. The ATS memory scheme is inherently fast and broadband, and, in contrast to the related schemes, is less demanding in terms of technical resources, making it a leading candidate for practical quantum technologies. Building on these ideas, we are also exploring using warm atoms in microwave cavities for other atomic quantum technologies.
Nov. 30, 2020 at 2:30 p.m.
Zoom