Scientists at Argonne National Laboratory and the University of Chicago have developed an advanced computer modeling method that enables accurate prediction and fine-tuning of key magnetic properties in molecular qubits. This breakthrough advances the understanding of how to design more reliable and efficient qubits, crucial components for the next generation of quantum technologies.
Qubits serve as the fundamental units of information processing in quantum devices. Improving their design and longevity has significant implications for the future capabilities of quantum computers and sensitive detectors used in medicine, navigation, and other fields. The research team focused on chromium-based molecular qubits—molecules embedded inside a crystal lattice—and successfully predicted how their zero-field splitting (ZFS) values, a critical magnetic property tied to qubit control, respond to variations in the host material.
The team identified two primary factors that influence ZFS tuning: the geometry of the crystal surrounding the chromium centers and the electric fields generated by the crystal’s chemical makeup. Their computational protocol not only matches experimental results but also allows scientists to estimate qubit coherence times, which determine how long a qubit can retain quantum information prior to degradation.
Led by University of Chicago Professor Giulia Galli, a senior scientist at Argonne and Liew Family Professor of electronic structure and simulations, the research underscores the value of interdisciplinary collaboration among chemists, material scientists, and physicists. Postdoctoral researcher Michael Toriyama described the method as a fully computational approach that establishes design rules tailored to various quantum applications, including communication, sensing, and computing.
This work marks the first time that control of ZFS through manipulation of electric fields in the host crystal has been identified and computationally verified for chromium molecular qubits. The ability to tune qubit properties flexibly stands in contrast to other qubit types, which offer more limited modification options.
The findings were published in the Journal of the American Chemical Society and supported by Q-NEXT, a U.S. Department of Energy National Quantum Information Science Research Center led by Argonne.
This progress offers a new path to optimize molecular qubits by accounting for both the qubit’s intrinsic electronic and spin properties and its surrounding environment, potentially accelerating advancements in quantum technology development.