Researchers at the University of Amsterdam and the University of New South Wales have resolved a decades-old question about ytterbium ions by demonstrating they can enter long-lived, nearly stable states. The team measured the duration of these states for the first time, opening potential applications in quantum computing and atomic clock technology.
Ytterbium, a rare earth metal, has long interested physicists studying quantum systems. The key breakthrough involves metastable states, where electrons occupy higher energy levels but remain trapped there far longer than expected. These states resist the natural tendency of electrons to drop to lower energy levels and release radiation, a process that typically occurs almost instantly.
The extended lifetimes matter enormously for practical quantum technology. In quantum computers, holding quantum information without degradation requires qubits to maintain their states for extended periods. Ytterbium ions serve as excellent qubits because of their favorable electronic properties and relatively low error rates. Longer-lived metastable states mean quantum information persists longer before decoherence ruins calculations.
For atomic clocks, the stability of these states directly determines clock precision. Atomic clocks work by tracking transitions between energy levels in atoms or ions. Clocks based on narrow transitions between long-lived states achieve unprecedented accuracy because the transitions occur so precisely and the states persist so long that environmental disturbances have minimal effect.
The Amsterdam and UNSW collaboration joins other efforts worldwide to exploit ytterbium's quantum properties. Researchers including teams at places like the National Institute of Standards and Technology have invested years developing ytterbium-based approaches. This work represents incremental but meaningful progress toward devices that could reshape timekeeping and quantum computation.
The measurements themselves required sophisticated laser spectroscopy and ion trapping techniques. The team confined ytterbium ions using electromagnetic fields and probed their energy states with precisely tuned lasers. The resulting data characterizes how