@article {2144, title = {Photon Subtraction by Many-Body Decoherence}, year = {2018}, month = {2018/03/13}, abstract = {

We present an experimental and theoretical investigation of the scattering-induced decoherence of multiple photons stored in a strongly interacting atomic ensemble. We derive an exact solution to this many-body problem, allowing for a rigorous understanding of the underlying dissipative quantum dynamics. Combined with our experiments, this analysis demonstrates a correlated coherence-protection process, in which the induced decoherence of one photon can preserve the spatial coherence of all others. We discuss how this effect can be used to manipulate light at the quantum level, providing a robust mechanism for single-photon subtraction, and experimentally demonstrate this capability.

}, doi = {https://doi.org/10.1103/PhysRevLett.120.113601}, url = {https://arxiv.org/abs/1710.10047}, author = {Callum R. Murray and Ivan Mirgorodskiy and Christoph Tresp and Christoph Braun and Asaf Paris-Mandoki and Alexey V. Gorshkov and Sebastian Hofferberth and Thomas Pohl} } @article {1834, title = {Many-body decoherence dynamics and optimised operation of a single-photon switch}, journal = {New Journal of Physics}, volume = {18}, year = {2016}, month = {2016/09/13}, pages = {092001}, abstract = {

We develop a theoretical framework to characterize the decoherence dynamics due to multi-photon scattering in an all-optical switch based on Rydberg atom induced nonlinearities. By incorporating the knowledge of this decoherence process into optimal photon storage and retrieval strategies, we establish optimised switching protocols for experimentally relevant conditions, and evaluate the corresponding limits in the achievable fidelities. Based on these results we work out a simplified description that reproduces recent experiments [arXiv:1511.09445] and provides a new interpretation in terms of many-body decoherence involving multiple incident photons and multiple gate excitations forming the switch. Aside from offering insights into the operational capacity of realistic photon switching capabilities, our work provides a complete description of spin wave decoherence in a Rydberg quantum optics setting, and has immediate relevance to a number of further applications employing photon storage in Rydberg media.\ 

}, doi = {10.1088/1367-2630/18/9/092001}, url = {http://iopscience.iop.org/article/10.1088/1367-2630/18/9/092001}, author = {Callum R. Murray and Alexey V. Gorshkov and Thomas Pohl} }