Investigation of Clock Transitions in Single and Coupled Molecular Spin Qubits

Florida State University, Tallahassee FL

Investigators

Abstract

With support from the Chemical Structure, Dynamics & Mechanisms-B (CSDM-B) Program of the Chemistry Division, Professors Mykhailo Shatruk of the Department of Chemistry and Biochemistry and Stephen Hill of the Department of Physics and National High Magnetic Field Laboratory at Florida State University are investigating approaches to magnetic molecules that can serve as qubits for quantum information processing. The project focuses on lanthanide complexes with quantum clock transitions, which can provide protection of the molecular qubits against external magnetic noise and prolong the duration of quantum entanglement – a crucial factor for the implementation of quantum technologies. The project will train junior scientists at the nexus of inorganic chemistry, quantum physics, and materials science, thus contributing to the education of the future quantum workforce. The project team plans to organize a nationwide undergraduate summer school to educate students about magnetic materials. Outreach activities will also involve high-school students and the general public, and are aimed at broadening participation by members of groups underrepresented in physical sciences. Paramagnetic molecular complexes are promising platforms for the development of electron spin qubits, due to the high tunability of their synthesis that allows realization of targeted magnetic parameters. This project will involve the examination of lanthanide complexes as potential electron spin qubits, with a focus on quantum clock transitions (QCTs) that emerge from the opening of quantum tunneling gaps due to mixing of ground doublet states generated by crystal field splitting. At the QCT, electron spin becomes insensitive to the surrounding spin bath, leading to a dramatic increase in the quantum coherence time, thus allowing protection of the entangled state from the magnetic noise. The first stage of this project involves the investigation of mononuclear complexes to identify the most promising QCT systems that demonstrate the desired values of tunneling gap and coherence time. The second stage will be devoted to connecting such qubits through a photo- or redox-switchable linkers, to make possible quantum gate operations. Advanced characterization methods, including a suite of electron paramagnetic resonance techniques, far-infrared magnetic spectroscopy, inelastic neutron scattering, and theoretical modeling will be used to investigate the molecular qubits and guide further synthetic efforts. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.