Spin Chains as Data Buses, Logic Buses and Entanglers

In this contribution, we describe some uses of the nonequilibrium dynamics of a spin chain in connecting remote registers for scalable quantum information processing. We first present a brief motivation, and a basic scheme to illustrate the idea of quantum state transfer through a spin chain. This is followed by an outline survey (by no means exhaustive) of the progress to date. We then describe one of the recently proposed methods which provides a high fidelity state transfer with minimal engineering, encoding and control. Next we present a couple of protocols for using nonequilibrium dynamics induced by quenches for establishing entanglement between well separated spins - these use the natural entanglement in a canonical condensed matter system, namely the Kondo system, but convert it to a useful form through the dynamics. Finally the possibility of usage of spin chains for quantum logic between remote registers is discussed along with a specific application to atomic systems.