Quantum-gate implementation in permanently coupled AF spin rings without need of local fields

TL;DR

This paper presents a method to implement quantum gates using antiferromagnetic molecular rings, enabling gate operations without local magnetic fields by engineering intercluster couplings and exploiting auxiliary states.

Contribution

It introduces a scheme for quantum gate implementation in AF spin rings that avoids local field control by engineering effective couplings and using auxiliary states.

Findings

Effective coupling vanishes in the computational space.

Gate operations are achieved via selective excitation of auxiliary states.

No need for local magnetic fields to perform single- and two-qubit gates.

Abstract

We propose a scheme for the implementation of quantum gates which is based on the qubit encoding in antiferromagnetic molecular rings. We show that a proper engineering of the intercluster link would result in an effective coupling that vanishes as far as the system is kept in the computational space, while it is turned on by a selective excitation of specific auxiliary states. These are also shown to allow the performing of single- and two-qubit gates without an individual addressing of the rings by means of local magnetic fields.