# Physicists Catch Light's Hidden Sideways Push on a Single Atom

*2026-09-13 22:01 UTC · Science · 1 min read*

> Physicists at PSI and ETH Zurich directly observed the optical Magnus effect for the first time, showing a focused laser interacts most strongly with an atom slightly off-beam-center — a finding with implications for quantum computer precision.

Researchers at the Paul Scherrer Institute and ETH Zurich have experimentally confirmed the optical Magnus effect, a subtle quantum phenomenon where a tightly focused laser beam interacts most strongly with an atom slightly off-center from the beam itself — not dead-center as long assumed.

The team used a single calcium ion, held nearly motionless in an electromagnetic trap, as an ultra-sensitive probe. By nudging the ion through different points of a focused laser beam and measuring the interaction strength at each position, they detected a sideways shift of just hundreds of nanometers. The size of the shift depends only on the light's wavelength, not on how tightly the beam is focused, matching a theoretical prediction made years earlier by researchers at the University of Amsterdam.

The effect matters for quantum computing: lasers are widely used to control individual atoms as qubits with extreme precision, and this hidden displacement could be a source of unwanted errors, or decoherence. But the researchers say the same effect might instead be harnessed as a new tool for coupling qubits together. The work was published in Physical Review Letters, with Philip Leindecker as lead author.

## Sources

- [sciencedaily.com](https://www.sciencedaily.com/releases/2026/09/260912220025.htm)
- [journals.aps.org](https://journals.aps.org/prl/abstract/10.1103/kj5p-qqs5)

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TechTools News · https://techtools.cz/tools/news/article/2367-physicists-catch-light-s-hidden-sideways-push-on-a-single-atom
Česká verze: https://techtools.cz/tools/news/clanek/2440-fyzici-zachytili-skryty-bocni-posun-svetla-u-jednoho-atomu