A Clock Transition in the Cr7Mn Molecular Nanomagnet

Charles Collett,Jonathan Friedman,Grigore Timco,Kevin Kittilstved,Nicholas Russo,Richard Winpenny,Kai-Isaak Ellers

doi:10.3390/magnetochemistry5010004

Charles Collett, Jonathan Friedman + Show 5 more

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https://doi.org/10.3390/magnetochemistry5010004

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Abstract

A viable qubit must have a long coherence time T 2 . In molecular nanomagnets, T 2 is often limited at low temperatures by the presence of dipole and hyperfine interactions, which are often mitigated through sample dilution, chemical engineering and isotope substitution in synthesis. Atomic-clock transitions offer another route to reducing decoherence from environmental fields by reducing the effective susceptibility of the working transition to field fluctuations. The Cr7Mn molecular nanomagnet, a heterometallic ring, features a clock transition at zero field. Both continuous-wave and spin-echo electron-spin resonance experiments on Cr7Mn samples, diluted via co-crystallization, show evidence of the effects of the clock transition with a maximum T 2 ∼ 390 ns at 1.8 K. We discuss improvements to the experiment that may increase T 2 further.

Highlights

The fundamental building block of a quantum computer is a qubit, a two-level system that can be in a superposition of the two levels
We have presented here results from both CW and pulsed experiments exploring a possible clock transition in the MNM Cr7 Mn
The CW results suggest the presence of a clock transition through a field-dependent saturation peak at higher radiation powers, centered around zero field

Summary

Introduction

The fundamental building block of a quantum computer is a qubit, a two-level system that can be in a superposition of the two levels. The ideal qubit would feature a quantum state with a long lifetime that is able to be precisely controlled and measured, as well as coupled to an array of other such qubits in a controllable manner. The engineerability of MNMs affords the ability to couple multiple MNMs together to create multi-qubit systems [4,7,8,9]. In order for such systems to be viable qubits, the coherence time T2 needs to be long compared to the time required for quantum gates. We present experimental results showing an enhancement of T2 in the Cr7 Mn MNM through the use of a so-called atomic-clock transition

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Results

Conclusion