Manipulation and Measurement of Nonclassical States of Light with Atomic Ensembles

Michal P. Parniak, Michał Dąbrowski, Mateusz Mazelanik +3 more

We demonstrate a quantum memory based on cold atomic ensemble generating and storing nonclassical light in 665 modes. With novel spin-wave manipulation techniques our system surfaces as a universal platform for quantum state preparation.

Rahul Trivedi, Daniil M. Lukin, Jelena Vuckovic A

T. Takano, Shin-Ichi-Ro Tanaka, Ryo Namiki +1 more

We report successful manipulation of nonclassical atomic spin states. We apply an off-resonant noncircularly-polarized light pulse to a measurement-induced squeezed spin state of a cold atomic ensemble. By changing the pulse duration, we clearly observe a rotation of the anisotropic quantum-noise distribution in good contrast with the case of manipulation of a coherent spin state where the quantum-noise distribution is always isotropic. This is an important step for quantum state tomography, quantum swapping, and precision spectroscopic measurement.

Brian J. Smith

Hyukjoon Kwon, Kok Chuan Tan, Tyler J. Volkoff +1 more

Julien Vaneecloo, Sébastien Garcia, Alexei Ourjoumtsev

We demonstrate a new versatile building block for optical quantum technologies, enabling deterministic quantum engineering of light by combining the advantages of two complementary approaches: cavity quantum electrodynamics and interacting atomic ensembles.Our system is based on an intracavity Rydberg-blockaded atomic ensemble acting as a single two-level superatom.We coherently control its state and optically detect it in a single shot with 95% efficiency.Crucially, we demonstrate a superatom-statedependent π phase rotation on the light reflected from the cavity.Together with the state manipulation and detection, it is a key ingredient for implementing deterministic photonic entangling gates and for generating highly nonclassical light states.