Measurement-Assisted Quantum Communication in Spin Channels with Dephasing

TL;DR

This paper introduces a measurement-based protocol to enhance quantum state transfer fidelity over noisy spin channels affected by dephasing, outperforming traditional methods and enabling robust entangling gates.

Contribution

It presents a novel measurement-assisted scheme that suppresses dephasing effects in quantum communication, functioning effectively where dynamical decoupling fails.

Findings

Significantly improves fidelity of quantum state transfer in noisy channels

Enables robust two-qubit entangling gates over long distances

Success probability can be optimized by tuning measurement rate

Abstract

We propose a protocol for countering the effects of dephasing in quantum state transfer over a noisy spin channel weakly coupled to the sender and receiver qubits. Our protocol, based on performing regular global measurements on the channel, significantly suppresses the nocuous environmental effects and offers much higher fidelities than the traditional no-measurement approach. Our proposal can also operate as a robust two-qubit entangling gate over distant spins. Our scheme counters any source of dephasing, including those for which the well established dynamical decoupling approach fails. Our protocol is probabilistic, given the intrinsic randomness in quantum measurements, but its success probability can be maximized by adequately tuning the rate of the measurements.