We have measured transport through mesoscopic Aharonov-Bohm (AB) rings with two different four-terminal configurations. While the amplitude and the phase of the AB oscillations are well explained within the framework of the Landaur-B\"uttiker formalism, it is found that the probe configuration strongly affects the coherence time of the electrons, i.e., the decoherence is much reduced in the configuration of so-called nonlocal resistance. This result should provide an important clue in clarifying the mechanism of quantum decoherence in solids.
@article{arxiv.cond-mat/0204186,
title = {Probe-Configuration-Dependent Decoherence in an Aharonov-Bohm Ring},
author = {Kensuke Kobayashi and Hisashi Aikawa and Shingo Katsumoto and Yasuhiro Iye},
journal= {arXiv preprint arXiv:cond-mat/0204186},
year = {2009}
}