A team of researchers led by Professor David Awschalom at the University of Chicago, in collaboration with scientists from the University of California Berkeley, Argonne National Laboratory, and Lawrence Berkeley National Laboratory, has developed molecular qubits capable of operating at telecommunications frequencies. This breakthrough represents a significant step toward integrating quantum technologies with existing fiber-optic networks and could accelerate the development of future quantum communication systems.
Weiss, L. R., Smith, G. T., Murphy, R. A., Golesorkhi, B., Méndez Méndez, J. A., Patel, P., Niklas, J., Poluektov, O. G., Long, J. R., & Awschalom, D. D. (2025). A high-resolution molecular spin-photon interface at telecommunication wavelengths. Science, 390(6768), 76–81. https://doi.org/10.1126/science.ady8677
The research, published in Science, demonstrates that these molecular qubits, which incorporate the rare-earth element erbium, can bridge the gap between light and magnetism. By encoding information in the magnetic state of a molecule and accessing it with light at wavelengths compatible with optical fiber networks and silicon photonic circuits, the team has created a building block that could support scalable quantum networks, often referred to as the “quantum internet.”
Professor David Awschalom at the University of Chicago stated,
“By demonstrating the versatility of these erbium molecular qubits, we’re taking another step toward scalable quantum networks that can plug directly into today’s optical infrastructure.”
Leah Weiss, a postdoctoral scholar at the University of Chicago Pritzker School of Molecular Engineering and co-first author of the study, explained that these molecular qubits act as a nanoscale interface between magnetic and optical systems. “Information could be encoded in the magnetic state of a molecule and then accessed with light at wavelengths compatible with well-developed optical infrastructure,” she said.
Grant Smith, a graduate student and co-first author, emphasized the potential for unconventional applications of these molecules. By expanding the range of quantum systems and materials that can be controlled, the team envisions integrating molecular qubits into hybrid devices for computing, communication, and sensing.
The molecular qubits are synthesized using erbium because of its unique optical and magnetic properties. Rare-earth elements are particularly useful for quantum applications because they absorb and emit light cleanly and interact strongly with magnetic fields. The researchers combined expertise in quantum optics and synthetic chemistry to design molecules that maintain these properties while being compatible with telecom frequencies.
Synthetic chemistry played a critical role in optimizing the electronic and optical properties of the erbium ions. Ryan Murphy, co-first author from the UC Berkeley team led by Professor Jeffrey Long, noted that molecular engineering allows for precise control of quantum materials in ways that are difficult with conventional solid-state systems. Professor Long added that designing quantum materials at the molecular level provides a pathway to tailor-made quantum systems suitable for networking, sensing, and computation.
Using optical spectroscopy and microwave techniques, the team confirmed that these molecular qubits can operate at frequencies compatible with silicon photonics. This compatibility with existing technology could significantly reduce the barrier to implementing molecular qubits in real-world quantum networks. Beyond communication, these qubits have potential as highly sensitive sensors. Their small size and chemical flexibility make them suitable for measuring magnetic fields, temperature, or pressure at the nanoscale, even in complex or biological environments.
Professor Awschalom highlighted that this research demonstrates the feasibility of scalable quantum networks that can integrate directly with today’s optical infrastructure. He noted that atomically engineered qubits like these could support multi-qubit architectures, opening the door to a range of applications including quantum sensing and hybrid quantum devices that combine organic and inorganic components.
Collaboration between physicists, chemists, and materials scientists was essential to this work. Weiss and Smith described their partnership with the Berkeley chemistry team as critical for achieving the molecular precision required for functional qubits. The study exemplifies how combining synthetic chemistry with quantum physics can produce new materials that bridge fundamental gaps between different technological platforms.
This research represents an important milestone in the pursuit of a quantum internet and compact quantum devices. By demonstrating that molecular qubits can operate at telecom frequencies, the team has provided a foundation for quantum networks that are both practical and compatible with existing infrastructure. Future work will focus on scaling these systems, integrating them into photonic circuits, and exploring applications in quantum computing, communication, and sensing.
Professor Awschalom concluded, “Our results show that molecular engineering can be used to create quantum systems with properties that were previously inaccessible, and this opens new opportunities for both fundamental science and technological applications.”
Adrian graduated with a Masters Degree (1st Class Honours) in Chemical Engineering from Chester University along with Harris. His master’s research aimed to develop a standardadised clean water oxygenation transfer procedure to test bubble diffusers that are currently used in the wastewater industry commercial market. He has also undergone placments in both US and China primarely focused within the R&D department and is an associate member of the Institute of Chemical Engineers (IChemE).
