  There has been much recent study on the application of spin chains to quantum
state transfer and communication. Here we demonstrate that spin chains set up
for perfect quantum state transfer can be utilised to generate remote quantum
gates, between spin qubits injected at the ends of the chain. The natural
evolution of the system across different excitation number sectors generates a
maximally-entangling and universal gate between the injected qubits,
independent of the length of the chain.
