We review the main theoretical and experimental results for the transmon, a superconducting charge qubit derived from the Cooper pair box. The increased ratio of the Josephson to charging energy results in an exponential suppression of the transmon's sensitivity to 1/f charge noise. This has been observed experimentally and yields homogeneous broadening, negligible pure dephasing, and long coherence times of up to 3 microseconds. Anharmonicity of the energy spectrum is required for qubit operation, and has been proven to be sufficient in transmon devices. Transmons have been implemented in a wide array of experiments, demonstrating consistent and reproducible results in very good agreement with theory.
@article{arxiv.0812.1865,
title = {Life after charge noise: recent results with transmon qubits},
author = {A. A. Houck and Jens Koch and M. H. Devoret and S. M. Girvin and R. J. Schoelkopf},
journal= {arXiv preprint arXiv:0812.1865},
year = {2009}
}
Comments
6 pages, 4 figures. Review article, accepted for publication in Quantum Inf. Proc