I present a general scheme through which the evidence of a superposition involving distinct classical-like states of a macroscopic system can be probed. The scheme relies on a qubit being coupled to a macroscopic harmonic oscillator in such a way that it can be used to both prepare and probe a macroscopic superposition. Two potentially realizable implementations, one with a flux qubit coupled to a LC circuit, and the other with an ion-trap qubit coupled to the collective motion of several ions, are proposed.
@article{arxiv.quant-ph/0308122,
title = {Qubit Assisted Probing of Coherence Between States of a Macroscopic Apparatus},
author = {Sougato Bose},
journal= {arXiv preprint arXiv:quant-ph/0308122},
year = {2007}
}