Identification of an X-Band Clock Transition in Cp′₃Pr^–Enabled by a 4f²5d¹Configuration

Abstract

Molecular qubits offer an attractive basis for quantum information processing, but challenges remain with regard to sustained coherence. Qubits based on clock transitions offer a method to improve the coherence times. We propose a general strategy for identifying molecules with high-frequency clock transitions in systems where a d electron is coupled to a crystal-field singlet state of an f configuration, resulting in an M J = ±1/2 ground state with strong hyperfine coupling. Using this approach, a 9.834 GHz clock transition was identified in a molecular Pr complex, [K(crypt)][Cp′ 3 Pr II ], leading to 3-fold enhancements in T 2 relative to other transitions in the spectrum. This result indicates the promise of the design principles outlined here for the further development of f-element systems for quantum information applications.

Ligand Effects on the Spin Relaxation Dynamics and Coherent Manipulation of Organometallic La(II) Potential Qudits

“…This near isotropic nature has some analogies with 2 S 1/2 state ions such as 171 Yb + used as hyperfine qubits in ion-trap QIS, and has been exploited to observe clock transitions (transitions at avoided level crossings where relaxation is prolonged because the transition frequency becomes insensitive to magnetic field fluctuations) at X-band microwave frequencies . The combination of such strategies with other approaches that exploit, for example, atomic clock transitions, , removal of nuclear spins, , or reduction of vibrational relaxation, − could sufficiently enhance molecular qubit properties without the need to apply a too high degree of magnetic dilution. This is particularly important for quantum computation as its implementation demands bringing qubits together and to perform qubit gates (logic operations) − to carry out specific algorithms.…”