For more than 30 years, the field of trapped-ion quantum computing has known it had a noise problem near chip surfaces — and had no precise way to measure it. Researchers at ETH Zurich published a technique in June 2026 that resolves both issues: a single trapped beryllium ion, suspended and repositioned above a quantum chip with micrometer precision, can now build a fully three-dimensional map of the electromagnetic fields that degrade quantum bits — and do so with sensitivity no previous instrument inside a chip trap has matched. For engineers building the next generation of quantum processors, the result means that a 30-year empirical guessing game about which chip materials produce the least noise can, for the first time, be replaced with direct measurement. The paper, by Tobias Sägesser, Shreyans Jain, and colleagues at the ETH Zurich Institute for Quantum Electronics — published online in Science Advances on June 19, 2026 — establishes a sensitivity record of 10 nanovolts per meter for oscillating electric fields, measured in a single second of wait time. For scale: the electromagnetic field from a mobile phone, measured from several kilometers away, is still roughly 10,000 times stronger than the signals the ETH team can now resolve at micrometer distances from a chip surface. Why Electric Field Noise Kills Quantum Bits Trapped-ion quantum computers store information in the electronic states of individual charged atoms, suspended in carefully designed electromagnetic fields and manipulated with laser pulses. In the early decades of the field, those traps filled entire rooms. Miniaturization has since compressed them onto millimeter-scale chips, bringing ions within a hair's breadth of a solid surface — and directly into the electromagnetic environment that surface creates. That proximity has a severe cost. Electric field noise originating from chip surfaces can jostle a trapped ion's motional