Researchers at the University of Oxford have demonstrated a new kind of quantum interaction using a single trapped ion. By carefully generating and controlling increasingly complex forms of "squeezing" -- including a fourth-order effect called quadsqueezing -- they have made quantum behaviors accessible that had previously been out of reach. The work also introduces a new way to engineer these interactions, with potential uses in quantum simulation, sensing, and computing. The findings were published today (May 1) in Nature Physics . Many physical systems behave like tiny oscillating objects, similar to springs or pendulums. In quantum physics, these are known as quantum harmonic oscillators. This description applies to a wide range of systems, including light waves, molecular vibrations, and even the motion of a single trapped atom. Controlling these oscillations is essential for modern quantum technologies.…