Constructing Clock-Transition-Based Two-Qubit Gates from Dimers of Molecular Nanomagnets

Abstract

A good qubit must have a coherence time long enough for gate operations to be performed. Avoided level crossings allow for clock transitions in which coherence is enhanced by the insensitivity of the transition to fluctuations in external fields. Because of this insensitivity, it is not obvious how to effectively couple qubits together while retaining clock-transition behavior. Here we present a scheme for using a heterodimer of two coupled molecular nanomagnets, each with a clock transition at zero magnetic field, in which all of the gate operations needed to implement one- and two-qubit gates can be implemented with pulsed radio-frequency radiation. We show that given realistic coupling strengths between the nanomagnets in the dimer, good gate fidelities ($\sim$99.4\%) can be achieved. We identify the primary sources of error in implementing gates and discuss how these may be mitigated, and investigate the range of coherence times necessary for such a system to be a viable platform for implementing quantum computing protocols.

arXiv commentVersion accepted by Phys. Rev. Research. Fig. 1 has minor modifications. References added

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• Time Crystals from single-molecule magnet arrays
• Clock Transitions Generated by Defects in Silica Glass
• Enhancing Coherence with a Clock Transition and Dynamical Decoupling in the Cr${}_7$Mn Molecular Nanomagnet