What does this mean for quantum computers?

Lasers often change the states of qubits — the basic memory units of a quantum computer — with very high precision. If engineers ignore the sideways shift, the optical Magnus effect could introduce small miscalibrations into qubit control.

Quantum computers store information in delicate quantum states that collapse under noise, so any unintended nudge can corrupt a calculation. The discovery gives experimentalists a previously invisible knob in their high-precision toolbox.

The team also sees a possible upside. "The forces it generates could be used to couple qubits to one another, enabling more complex computations," says first author Philip Leindecker of the PSI Center for Photon Science and ETH Zurich.

The claim is preliminary: it rests on one experiment in a controlled laboratory setting, and the implications for full-scale quantum hardware remain speculative.

How did the researchers measure such a tiny shift?

The team used a single calcium ion held nearly motionless in an electromagnetic ion trap as a microscopic probe.

Such trapped ions are themselves a leading candidate for building qubits. Ion traps hold charged atoms in place using oscillating electromagnetic fields, isolating them from thermal noise. That isolation lets physicists perform measurements with very high precision, including shifts smaller than the wavelength of the probing light.

The researchers moved the calcium ion through different parts of the tightly focused laser beam and recorded how strongly it interacted with the light at each position.

"Our ion acts like a tiny sensor that we can use to feel out the structure of the laser light," Leindecker explains. "This makes it possible to measure a shift of just a few hundred nanometers."

What did the measurement reveal about the effect's behavior?

The size of the sideways shift depends only on the wavelength of the light, the team found, not on how tightly the beam is focused. That scaling rule, which matches the Amsterdam prediction, makes the effect easier to forecast and, perhaps, to exploit in designing optical systems.

What remains uncertain?

• The result comes from one ion in one apparatus; broader testing in multi-qubit ion traps would strengthen the case.
• Whether the sideways shift is large enough to cause real errors in working quantum computers is not yet known.
• The proposal to use the effect as a coupling mechanism between qubits remains theoretical; no demonstration exists yet.

Key numbers at a glance

• Publication date: September 13, 2026
• Journal: Physical Review Letters, 137 (6)
• DOI: 10.1103/kj5p-qqs5
• Measured shift: a few hundred nanometers
• Probe: single calcium ion
• Lead author: Philip Leindecker (PSI / ETH Zurich)