We investigate qubit measurements using a single electron transistor (SET). Applying the Schr\"odinger equation to the entire system we find that an asymmetric SET is considerably more efficient than a symmetric SET. The asymmetric SET becomes close to an ideal detector in the large asymmetry limit. We also compared the SET detector with a point-contact detector. This comparison allows us to illuminate the relation between information gain in the measurement process and the decoherence generated by these measurement devices.
@article{arxiv.cond-mat/0408051,
title = {Single qubit measurements with an asymmetric single-electron transistor},
author = {S. A. Gurvitz and G. P. Berman},
journal= {arXiv preprint arXiv:cond-mat/0408051},
year = {2009}
}
Comments
4 pages, more explanations added, Phys. Rev. B, in press