Robust transmission of non-Gaussian entanglement over optical fibers
Asoka Biswas, Daniel A. Lidar · Physical Review A · 2006
We show how the entanglement in a wide range of continuous variable non-Gaussian states can be preserved against decoherence for long-range quantum communication through an optical fiber. We apply protection via decoherence-free subspaces and quantum dynamical decoupling to this end. The latter is implemented by inserting phase shifters at regular intervals $\ensuremath{\Delta}$ inside the fiber, where $\ensuremath{\Delta}$ is roughly the ratio of the speed of light in the fiber to the bath high-frequency cutoff. Detailed estimates of relevant parameters are provided using the boson-boson model of system-bath interaction for silica fibers and $\ensuremath{\Delta}$ is found to be on the order of a millimeter.