Superconducting circuits can behave like atoms making transitions between two levels. Such circuits can test quantum mechanics at macroscopic scales and be used to conduct atomic-physics experiments on a silicon chip.
@article{arxiv.quant-ph/0601121,
title = {Superconducting Circuits and Quantum Information},
author = {J. Q. You and Franco Nori},
journal= {arXiv preprint arXiv:quant-ph/0601121},
year = {2009}
}
Comments
7 pages, 4 figures. See also: http://www.physicstoday.org/vol-58/iss-11/contents.html