Noise to lubricate qubit transfer in a spin network

TL;DR

This paper demonstrates that adding specific Gaussian white noise to a fully connected spin network can significantly improve quantum state transfer fidelity, even in large networks, by overcoming limitations of free dynamics.

Contribution

It introduces a noise-assisted method for high-fidelity quantum state transfer in spin networks, showing noise can be beneficial rather than detrimental.

Findings

Noise enhances fidelity close to one

Benefit applies to networks of any size

Fidelity depends on noise strength and affected edges

Abstract

We consider quantum state transfer in a fully connected spin network, in which the results indicate that it is impossible to achieve high fidelity by free dynamics. However, the addition of certain kinds of noise can be helpful for this purpose. In fact, we introduce a model of Gaussian white noise affecting the spin-spin couplings (edges), except those linked to the input and output node, and prove that it enhances the fidelity of state transfer. The observed noise benefit is scale free as it applies to a quantum network of any size. The amount of the fidelity enhancement, depending on the noise strength as well as on the number of edges to which it is applied, can be so high as to take the fidelity close to one.