Realizing Qubits with Laser Trapped Neutral Atoms of Two Different Elements

Quantum computing requires a coherent, high fidelity, and scalable qubits. Trapped ion or superconducting qubits are the current research focus. But an emerging qubit implementation is trapped neutral atoms. Neutral atoms are trapped in place using carefully tuned lasers, instead of electrical potentials or electromagnetic fields. The biggest advantage of this approach is that the neutral atoms are suspended in vacuum and experience little environmental interaction. So they remain coherent for a very long time.

The traditional way to scale this system is to use a grid of neutral atoms. But they tend to be destructive as all the atoms have the same resonance frequency. To get around, researchers at the University of Chicago created an array of alternating atoms. They used neutral rubidium and cesium atoms. Each atom only sees an atom of a different element as its closest neighbor. So it overcomes the problem of the grid collapsing due to resonance.

Another problem solved by this approach is that traditional qubits have to be re-initialized in a coherent state. The entire qubit system needs to be reloaded. But by treating the single qubit grid as two independent atom grids, the researchers are able to refresh one grid while maintaining the other one. That way qubits are always available.

The advancement serves as one more stepping stone towards realizing full-scale quantum computing.

Source: https://journals.aps.org/prx/abstract/10.1103/PhysRevX.12.011040