Quantum state tomography is an important tool in quantum information science for complete characterization of multi-qubit states and their correlations. Here we report a method to perform a joint simultaneous read-out of two superconducting qubits dispersively coupled to the same mode of a microwave transmission line resonator. The non-linear dependence of the resonator transmission on the qubit state dependent cavity frequency allows us to extract the full two-qubit correlations without the need for single shot read-out of individual qubits. We employ standard tomographic techniques to reconstruct the density matrix of two-qubit quantum states.
@article{arxiv.0812.2485,
title = {Two-Qubit State Tomography using a Joint Dispersive Read-Out},
author = {S. Filipp and P. Maurer and P. J. Leek and M. Baur and R. Bianchetti and J. M. Fink and M. Göppl and L. Steffen and J. M. Gambetta and A. Blais and A. Wallraff},
journal= {arXiv preprint arXiv:0812.2485},
year = {2009}
}
Comments
4 pages, 4 figures, version with high resolution figures available at http://qudev.ethz.ch/content/science/PubsPapers.html