For many years, physicists saw quantum non-commutativity as a problem. When two quantum forces acted on the same particle in the wrong order, they would interfere with each other and ruin measurements. But scientists at the University of Oxford have now changed this nuisance into something useful.
On May 1, 2026, the Oxford team published their findings in Nature Physics. They reported the first experimental observation of quadsqueezing, a fourth-order quantum interaction that was previously thought too weak to measure. The experiment used a single trapped ion.
Squeezing is a quantum technique that reshapes uncertainty. In quantum mechanics, certain pairs of properties like position and momentum cannot both be measured perfectly. Squeezing makes one sharper while making the other less precise. Standard squeezing already helps the LIGO gravitational-wave detector work better.
But higher-order versions like trisqueezing and quadsqueezing are much harder to observe because the interactions are very faint and disappear into background noise. The Oxford team, led by Dr Oana Băzăvan, solved this problem by applying two non-commuting forces to their trapped ion. Because these forces do not commute, their order matters, and each one amplifies the other. This created a fourth-order interaction 100 times faster than expected.
The researchers could switch between different squeezing levels using the same setup. This technique could help advance quantum sensors, simulators, and computers. The team did not need new particles or machines. They simply asked a different question of existing equipment, turning a weakness into strength.