Quantum Data Bus in Dipolar Coupled Nuclear Spin Qubits

TL;DR

This paper demonstrates a method for quantum state transfer and entanglement generation in a dipolar coupled nuclear spin chain using iterative procedures, effectively creating a quantum data bus in a liquid crystal NMR system.

Contribution

It introduces an iterative quantum state transfer protocol exploiting natural dipolar couplings, enabling high-fidelity transfer and entanglement in a nuclear spin chain.

Findings

Achieved asymptotic transfer fidelity approaching one.

Implemented a scheme for transferring states from chain end to any position.

Demonstrated entanglement generation between arbitrary spins.

Abstract

We implement an iterative quantum state transfer exploiting the natural dipolar couplings in a spin chain of a 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 the spin at the end point. The transfer fidelity reaches one asymptotically through increasing the number of iterations. We also implement the inverted version of the scheme which can transfer an arbitrary state from the end point to any other position of the chain and entangle any pair of spins in the chain, acting as a full quantum data bus.