A new quantum interaction involving a trapped single ion (19459000)
Many physical systems vibrate back and forth like pendulums or springs. Quantum harmonic oscillators are everywhere in quantum physics: the movement of an atom, the vibrating molecules and ripples in light. The ability to control these rhythms will lead to future quantum technologies ranging from highly precise sensors to new powerful computers.
The Squeezing technique is one of the best ways to take over. Quantum mechanics has a hard limit. Certain pairs of properties such as momentum and position cannot be perfectly known at the same moment. The squeeze pushes the limit of this law, sharpening and degrading both properties, thus distorting the uncertainty. It is not a curious phenomenon, but it does help detectors like LIGO to hear the subtle eddies created by gravitational wave ripples in spacetime.
Squeezing alone is not enough.
Since decades, physicists dreamed about doing more: deeper and richer control types known as quadsqueezing or trisqueezing. These higher-order quantum interactions are yet to be discovered experimentally, but they promise more powerful and complex quantum behavior. The reason is simple: as order increases, effects become weaker and more susceptible to noise.
The University of Oxford physicists used ancient Greek dance to convince a trapped, single ion, which was once considered impossible, to move. Quantum rhythms have taken on new dimensions as they’ve transformed the squeezing into higher-order effects that were previously out of reach. Quadsqueezing is one such interaction, which was previously confined to the realm of theory.
Researchers have now made experimentally available these previously elusive quantum phenomena.
This is an important technical breakthrough: A new way to engineer the quantum interactions. Researchers can now run detailed simulations, improve the accuracy of quantum sensors and find new ways to build powerful quantum computers.
The lead author of the study, Dr. Oana Bazvan from Department of Physics at Oxford University, stated: In the laboratory, non-commuting interaction is often considered a nuisance as they introduce undesirable dynamics. We used this feature in the reverse direction to create stronger quantum interactions.
The Oxford group used a more complex approach than simply bending the weaker higher-order quantum effects. Researchers used two forces that were finely calibrated to act on one trapped ion. This was in accordance with a theory first proposed by Raghavendra Shrinivas and Robert Tyler Sutherland back in 2021.
Each force can be described as a linear, simple movement. When the two forces interact, however, they produce a different effect: an ion that is more powerful than the interaction between the two.
The non-commutativity principle is responsible for this surprising synergy. When you move into the quantum realm, the first thing to change is the order in which operations are performed. The two forces, on the contrary, do not sum up; instead, they work together in synergy to influence each other more powerfully and complexly.
Researchers at Oxford discovered that, on the same stage of experimentation, they were able to play their trapped ion’s tune as an orchestra conductor would.
They were able to switch between the different quantum “squeezing” forms by fine-tuning frequencies, phase and intensity of forces.
The researchers turned a knob in spacetime to choose which quantum symphony they wanted to play through the reality and muted all unwanted instruments.
Dr. Oana Bazavan said: The result of the experiment is much more than a quantum state. The new technique demonstrates how to engineer interactions previously unattainable.
It was 100 times quicker than conventional methods to generate the fourth-order quadsqueezing interactions. It is now possible to achieve effects previously unattainable in reality.”
Journal Reference
- Bazavan, O., Saner, S., Webb, D.J. Bazavan, O., Saner S. Squeezing trisqueezing or quadsqueezing a hybrid oscillator/spin system.
Nat. Phys.
(2026). DOI: 10.1038/s41567-026-03222-6
