Crystal imperfections may yield better quantum connections

Building large-scale quantum devices means connecting many tiny quantum bits, or qubits, without destroying their delicate quantum states. A new theoretical study shows that crystal dislocations — long, line-like defects in a crystal often considered imperfections — could be used as parts of those connections.

The study was recently published in npj Computational Materials. Using detailed computer simulations, researchers led by Ohio State University Materials Science and Engineering Professor Maryam Ghazisaeidi and University of Chicago Professor Giulia Galli  studied nitrogen-vacancy (NV) centers in diamond. NV centers are a common type of solid-state qubit. The team found that NV centers are drawn toward dislocations and can keep their quantum properties when they sit near these defects. In some cases, the NV centers even showed improved quantum behavior. These findings suggest that what was once thought of as flaws might help build reliable links between qubits.

“Importantly, we predicted that specific NV configurations near dislocations exhibit significantly enhanced quantum coherence times compared to NV centers in pristine diamond,” said Ghazisaeidi.

This improvement arises from symmetry breaking near the dislocation, which creates specific states, called “clock transitions” that protect the qubit from environmental magnetic noise, she added.

Funded by the Air Force, the research brought together Ohio State and UChicago’s expertise in materials science, mechanical engineering, quantum information science and high-performance computing and directed by Galli.

The simulations carried out in the paper leveraged GPU-accelerated, massively parallel codes developed within the Midwest Integrated Center for Computational Materials (MICCoM), a computational materials science center funded by the Department of Energy at Argonne National Laboratory.

“Because dislocations form quasi-one-dimensional (1D) structures extending through a crystal, they provide a natural scaffold for arranging qubits into ordered arrays,” said co-first author Cunzhi Zhang, a UChicago PME staff scientist in the Galli Group.

Beyond establishing stability and coherence, the work provided detailed predictions of optical and magnetic resonance signatures that can guide experimental identification of useful NV–dislocation configurations. 

Researchers say that while not all defect arrangements are suitable for quantum operations, their results show that a substantial fraction meet the requirements for qubit functionality.

Overall, the study suggests a new way to design quantum devices. Rather than removing crystal dislocations, engineers could use them as quantum highways that host and link chains of interacting qubits. This idea could make it easier to build scalable quantum interconnects in diamond and possibly in other materials, offering a practical strategy for future solid‑state quantum technologies.

This work was supported by the AFOSR Grant No. FA9550-23-1-0330.

based on University of Chicago Pritzker School of Molecular Engineering press release