We study quantum state tomography, entanglement detection, and channel noise reconstruction of propagating quantum microwaves via dual-path methods. The presented schemes make use of the following key elements: propagation channels, beam splitters, linear amplifiers, and field quadrature detectors. Remarkably, our methods are tolerant to the ubiquitous noise added to the signals by phase-insensitive microwave amplifiers. Furthermore, we analyze our techniques with numerical examples and experimental data, and compare them with the scheme developed in Eichler etal (2011 Phys. Rev. Lett. 106 220503; 2011 Phys. Rev. Lett. 107 113601), based on a single path. Our methods provide key toolbox components that may pave the way towards quantum microwave teleportation and communication protocols.
@article{arxiv.1308.3117,
title = {Dual-Path Methods for Propagating Quantum Microwaves},
author = {R. Di Candia and E. P. Menzel and L. Zhong and F. Deppe and A. Marx and R. Gross and E. Solano},
journal= {arXiv preprint arXiv:1308.3117},
year = {2014}
}