Inside a radio-frequency trap at Oxford’s Clarendon Laboratory, a single strontium ion hangs in a vacuum, cooled to near stillness, vibrating with an energy so close to nothing that quantum mechanics itself sets the floor. The ion is about ten nanometres across. Its motion is the harmonic oscillator, the same mathematical beast that describes a child’s swing, a plucked guitar string, the electromagnetic shiver of light itself. For decades, physicists have been squeezing that motion, redistributing its quantum uncertainty to sharpen one property at the cost of another. What Oana Băzăvan and her colleagues at Oxford have now done is push the squeezing to a place no one has gone before. The result, published in Nature Physics, is something called quadsqueezing: a fourth-order quantum interaction that, until now, existed mostly as a theoretical curiosity. Getting there required a trick that was, in a way, hiding in plain sight. The Quantum Noise Problem Squeezing is already a workhorse of precision physics. It works because quantum mechanics does not let you know everything about a system at once. Position and momentum, for instance, cannot both be pinned down simultaneously; this is Heisenberg’s uncertainty principle, not as a failure of measurement but as a hard feature of reality. Squeezing reshapes that uncertainty: make position sharper and momentum gets blurrier, or vice versa. Squeezed light is already used in gravitational-wave detectors like LIGO, where the sensitivity needed to catch the faint ripple of two colliding black holes requires beating quantum noise itself. Ordinary, second-order squeezing does that job. But physicists have long suspected that going further, to third-order (trisqueezing) and fourth-order (quadsqueezing) interactions, would unlock genuinely different quantum territory. Non-Gaussian states, they are called, and they matter because the classical computers that can efficiently simulate ordinary Gaussian quantum systems hit a wall when the