  Building blocks of quantum computers have been demonstrated in small to
intermediate-scale systems. As one of the leading platforms, the trapped ion
system has attracted wide attention. A significant challenge in this system is
to combine fast high-fidelity gates with scalability and convenience in ion
trap fabrication. Here we propose an architecture for large-scale quantum
computing with a two-dimensional array of atomic ions trapped at such large
distance which is convenient for ion-trap fabrication but usually believed to
be unsuitable for quantum computing as the conventional gates would be too
slow. Using gate operations far outside of the Lamb-Dicke region, we show that
fast and robust entangling gates can be realized in any large ion arrays. The
gate operations are intrinsically parallel and robust to thermal noise, which,
together with their high speed and scalability of the proposed architecture,
makes this approach an attractive one for large-scale quantum computing.
