We propose an experimentally feasible architecture with controllable long-range couplings built up from local exchange interactions. The scheme consists of a spin-bus, with strong, always-on interactions, coupled dynamically to external qubits of the Loss and DiVincenzo type. Long-range correlations are enabled by a spectral gap occurring in a finite-size chain. The bus can also form a hub for multiqubit entangling operations. We show how multiqubit gates may be used to efficiently generate W-states (an important entanglement resource). The spin-bus therefore provides a route for scalable solid-state quantum computation, using currently available experimental resources.
@article{arxiv.quant-ph/0702228,
title = {Efficient multiqubit entanglement via a spin-bus},
author = {Mark Friesen and Asoka Biswas and Xuedong Hu and Daniel Lidar},
journal= {arXiv preprint arXiv:quant-ph/0702228},
year = {2009}
}