Quantum data bus in dipolar coupled nuclear spin qubits

摘要

We implement an iterative quantum state transfer exploiting the natural dipolar couplings in a spin chain ofa liquid-crystal NMR system. During each iteration, a finite part of the amplitude of the state is transferred and,by applying an external operation on only the last two spins, the transferred state is made to accumulate on thespin at the end point. The transfer fidelity reaches one asymptotically through increasing the number ofiterations. We also implement the inverted version of the scheme which can transfer an arbitrary state from theend point to any other position of the chain and entangle any pair of spins in the chain, acting as a full quantumdata bus.