Scientists at the University of Oxford have achieved something never done before in quantum physics: they created a new type of interaction called “quadsqueezing.”
This breakthrough could open new doors for quantum computing, ultra-sensitive measurements, and advanced simulations of complex systems.
To understand why this matters, it helps to start with a simple idea.
Many things in physics behave like tiny vibrating systems, similar to a swinging pendulum or a bouncing spring. In the quantum world, these are called quantum harmonic oscillators.
They describe everything from light waves to the motion of atoms.
Being able to control these tiny systems is essential for building powerful quantum technologies.
One important method scientists use is called squeezing. In quantum physics, there is a natural limit to how precisely you can measure certain pairs of properties, such as position and momentum.
If you try to measure one very accurately, the other becomes less certain. Squeezing works by redistributing this uncertainty.
It allows scientists to measure one property more precisely, even if it means giving up precision in the other. This technique is already used in real-world systems like gravitational-wave detection, helping observatories detect extremely faint signals from space.
However, standard squeezing is just the beginning.
Physicists have long wanted to create more complex versions, known as higher-order squeezing, including trisqueezing and quadsqueezing. These involve more complicated interactions and could unlock new types of quantum behavior.
The problem is that these higher-order effects are usually extremely weak and easily lost in background noise, making them very hard to observe.
The Oxford team found a clever way around this challenge. Instead of trying to directly produce a weak higher-order effect, they combined two carefully controlled forces acting on a single trapped ion. A trapped ion is an electrically charged atom held in place using electromagnetic fields, allowing scientists to manipulate it very precisely.
Each force on its own produces a simple effect. But when combined, something surprising happens.
Because of a property called non-commutativity, the two forces interact with each other in a way that creates a much stronger and more complex effect. In simple terms, the combined result is more powerful than the sum of its parts.
Using this method, the researchers were able to generate not only standard squeezing but also trisqueezing and, for the first time ever, quadsqueezing. Even more impressively, the quadsqueezing effect was created over 100 times faster than expected using traditional approaches. This makes it much easier to study and use in real experiments.
The team confirmed their results by carefully measuring the quantum state of the ion. Each type of squeezing produces a unique pattern, and the researchers were able to clearly identify the signatures of second-, third-, and fourth-order interactions.
This discovery is not just about creating a new quantum effect. It introduces a powerful new method for engineering complex quantum interactions that were previously out of reach. Because the technique uses tools that are already available in many quantum systems, it could be widely applied in the future.
Scientists believe this approach could help build better quantum computers, improve sensors that detect tiny signals, and allow researchers to simulate complex physical systems that are otherwise impossible to study.
By pushing into this new “uncharted territory,” the work marks an important step forward in understanding and controlling the quantum world.
Source: University of Oxford.
