Oxford Team Achieves First-Ever Quadsqueezing on a Single Trapped Ion, Generating the Fourth-Order Effect Over 100 Times Faster Than Expected

Overview

A team at the University of Oxford has demonstrated quadsqueezing, a fourth-order quantum interaction, on a single trapped ion, according to the University of Oxford Department of Physics. The result, published in Nature Physics on 1 May 2026 under the title “Squeezing, trisqueezing and quadsqueezing in a hybrid oscillator-spin system,” extends the family of quantum squeezing operations beyond the second- and third-order effects already known to experimentalists, as reported by ScienceDaily.

The Oxford group reports that the fourth-order quadsqueezing interaction was generated more than 100 times faster than expected using conventional approaches, according to Phys.org.

What We Know

Lead author Dr Oana Băzăvan, of Oxford’s Department of Physics, worked with co-author and supervisor Dr Raghavendra Srinivas to engineer the new interaction, as reported by The Quantum Insider. The experiment confined a single ion between electrode structures and controlled it with precisely tuned laser fields, according to ScienceDaily.

Rather than driving the ion with a single direct interaction, the team combined two carefully controlled forces whose effects do not commute. As Phys.org describes the technique, “when applied together, they produce a new interaction that is more than the sum of their parts.” The supporting theory was proposed by Srinivas and Robert Tyler Sutherland in 2021, according to Phys.org.

Dr Băzăvan framed the conceptual shift in the Oxford announcement: “In the lab, non-commuting interactions are often seen as a nuisance because they introduce unwanted dynamics. Here, we took the opposite approach and used that feature to generate stronger quantum interactions.” In further remarks reported by The Quantum Insider, Dr Băzăvan said: “The result is more than the creation of a new quantum state. It is a demonstration of a new method for engineering interactions that were previously out of reach.”

Dr Srinivas, in comments reported by The Quantum Insider, described the broader significance: “Fundamentally, we have demonstrated a new type of interaction that lets us explore quantum physics in uncharted territory.”

The same apparatus produced standard squeezing, trisqueezing, and quadsqueezing by adjusting the frequencies, phases, and strengths of the applied forces, with the ion’s quantum motion reconstructed through measurements that revealed distinct patterns for second-, third-, and fourth-order squeezing, according to ScienceDaily.

The authors point to applications across quantum simulation, quantum sensing, and quantum computing, as well as the simulation of lattice gauge theories, according to the Oxford announcement.

What We Don’t Know

The paper demonstrates the interaction on a single trapped ion under controlled laboratory conditions; how the technique scales to larger ion crystals or to other physical platforms is not addressed in the materials released alongside publication, which focus on the principle of using non-commuting forces to engineer higher-order interactions, per Phys.org. Translating the demonstration into concrete advantages for sensing or computing benchmarks will require follow-on experiments not described in the announcement.

The announcement also does not quantify how much improvement quadsqueezing can deliver over existing squeezing-based techniques in operational systems; the headline figure of “more than 100 times faster than expected using conventional approaches” refers to the speed at which the fourth-order interaction itself is generated relative to baseline expectations, according to Phys.org, and does not translate directly into an end-application speedup.