We discuss collapse and revival of Rabi oscillations in a system comprising a qubit and a "big spin" (made of N qubits, or spin-1/2 particles). We demonstrate a regime of behaviour analogous to conventional collapse and revival for a qubit-field system, employing spin coherent states for the initial state of the big spin. These dynamics can be used to create a "Schrodinger cat" state of the big spin. Even for relatively small values of N, states with significant potential for quantum metrology applications can result, giving sensitivity approaching the Heisenberg limit.
@article{arxiv.1302.2806,
title = {Collapse and Revival and Cat States with an N Spin System},
author = {Shane Dooley and Francis McCrossan and Derek Harland and Mark J. Everitt and Timothy P. Spiller},
journal= {arXiv preprint arXiv:1302.2806},
year = {2015}
}