Scientists at the University of Chicago have developed a molecular-scale qubit built around the rare-earth element erbium, capable of storing information magnetically and transmitting it optically at telecom-friendly wavelengths, tells Live Science. Unlike most qubits that are either purely spin-based or photon-based, this hybrid erbium qubit can link the magnetic (spin) world and the optical (photon) world, making it uniquely suited to bridge quantum devices with existing fiber optics.
Because it operates at wavelengths used in telecommunications, the device can travel long distances through optical fiber with minimal loss and can be processed via silicon-based photonic circuits. This compatibility matters: one of the major bottlenecks in scaling quantum networks is the challenge of integrating quantum hardware with the global infrastructure that supports classical data. The team demonstrated that the erbium atom’s spin state can be placed in a controlled superposition and then read out via optical spectroscopy, a key requirement for quantum computing and communications.
Importantly, the molecular qubit is extremely small, around 100,000 times finer than a human hair, and its structure can be synthetically tuned. This opens the door to embedding quantum nodes on chips or even within more complex solid-state architectures. In the recently published paper, the authors describe this work as “a promising new building block for scalable quantum technologies.”
While this is not yet a full quantum internet, the breakthrough significantly lowers one barrier by showing that quantum information can be encoded, transmitted, and read out using the same fiber-optic networks that underpin today’s global communication systems. The next steps will revolve around integrating these qubits into functioning on-chip systems and coupling them across longer distances.