Scientists have created a new way to generate powerful quantum interactions, achieving the first-ever demonstration of quadsqueezing.
This breakthrough makes previously hidden quantum effects visible and usable for advanced technologies.
Oxford Scientists Demonstrate First-Ever Quadsqueezing Quantum Interaction
Researchers at the University of Oxford have achieved a major advance in quantum physics by demonstrating a new kind of interaction using a single trapped ion. By carefully producing and controlling increasingly complex forms of “squeezing” – including a fourth-order effect called quadsqueezing – the team has made quantum behaviors observable that had previously been out of reach. The method also introduces a new way to design and control these interactions, with possible applications in quantum simulation, sensing, and computing. The findings were published on May 1 in Nature Physics.
Quantum Oscillators and Their Role in Technology
Many systems in physics behave like tiny vibrating objects, similar to springs or pendulums. In the quantum world, these are called quantum harmonic oscillators. This framework can describe light waves, molecular vibrations, and even the motion of a single trapped atom.
The ability to control these oscillations is essential for a range of quantum technologies, including extremely sensitive measurement devices and emerging quantum computers.
How Squeezing Improves Quantum Precision
One widely used method for controlling quantum oscillators is known as squeezing. In quantum mechanics, there are limits on how precisely certain pairs of properties, such as position and momentum, can be measured at the same time. Squeezing redistributes this uncertainty, allowing one property to be measured more precisely at the cost of increased uncertainty in the other.
This effect is already used in real-world applications. For example, squeezed light helps improve the sensitivity of gravitational-wave detectors such as LIGO.
Moving Beyond Standard Squeezing
Standard squeezing is only part of a broader class of interactions. Physicists have long aimed to create more complex versions, including trisqueezing and quadsqueezing. These higher-order effects are much harder to achieve because they are naturally very weak and become even weaker as the order increases. As a result, they are often lost to noise before they can be detected.
Combining Forces to Amplify Quantum Effects
To overcome this challenge, the Oxford team developed a new approach. Instead of directly trying to produce a weak higher-order interaction, they combined two precisely controlled forces acting on a single trapped ion. This method follows a theory proposed in 2021 by Dr. Raghavendra Srinivas and Robert Tyler Sutherland.
Each force alone produces a simple, predictable effect. When used together, however, they create a stronger interaction that goes beyond their individual contributions. This effect arises from non-commutativity, where the forces influence each other in a way that amplifies the resulting motion of the ion.
Lead author, Dr. Oana Băzăvan, Department of Physics, University of Oxford, said: “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.”
First Demonstration of Quadsqueezing
Using the same experimental setup, the researchers were able to switch between different types of squeezing. They produced standard squeezing, trisqueezing, and, for the first time on any platform, quadsqueezing, a fourth-order interaction. By adjusting the frequencies, phases, and strengths of the applied forces, they could control which interaction appeared while reducing unwanted effects.
Dr. Oana 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. The fourth-order quadsqueezing interaction was generated more than 100 times faster than expected using conventional approaches. This makes effects that were previously out of reach accessible in practice.”
Verifying the Quantum States
The team confirmed their results by reconstructing the quantum motion of the trapped ion. Their measurements revealed distinct patterns linked to second-, third-, and fourth-order squeezing. These patterns served as clear evidence that each type of interaction had been successfully produced.
Expanding Toward More Complex Quantum Systems
The researchers are now applying this method to more complex systems that involve multiple modes of motion. Because the technique uses tools that are already available in many quantum platforms, it could become a widely applicable method for studying advanced quantum behavior.
The approach has already been combined with mid-circuit measurements of the ion’s spin to create flexible superpositions of squeezed states and to simulate a lattice gauge theory.
Study co-author Dr. Raghavendra Srinivas (Department of Physics, University of Oxford), who supervised the work, said: “Fundamentally, we have demonstrated a new type of interaction that lets us explore quantum physics in uncharted territory, and we are genuinely excited for the discoveries to come.”
Reference: “Squeezing, trisqueezing and quadsqueezing in a hybrid oscillator–spin system” by O. Băzăvan, S. Saner, D. J. Webb, E. M. Ainley, P. Drmota, D. P. Nadlinger, G. Araneda, D. M. Lucas, C. J. Ballance and R. Srinivas, 1 May 2026, Nature Physics.
DOI: 10.1038/s41567-026-03222-6
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1 Comment
thanks for this