Monolithic printed-circuit board RF-trap for electrons

As quantum information processing moves toward alternative platforms, trapped electrons have emerged as a compelling candidate due to their simple two-level spin structure and the potential for fast gate operations using microwave signals. However, traditional Penning traps often suffer from anharmonicities, and existing chip-based traps can be difficult to assemble with high precision. This study investigates whether a monolithic, single-piece printed circuit board (PCB) can serve as a robust, high-performance Paul trap for individual electrons.

The researchers designed a Paul trap fabricated entirely from a single PCB substrate. By integrating the RF resonator and DC electrodes into one rigid body, the design avoids the alignment errors and manufacturing tolerances inherent in multi-component assemblies. The trap uses a half-wave coplanar resonator to provide radial confinement, while DC electrodes provide axial confinement. The team characterized the trap by loading electrons via photoionization of a thermal calcium beam and measuring the resulting electron lifetimes and secular motional frequencies using a microchannel plate (MCP) detector.

The monolithic PCB design successfully confined electrons, demonstrating a trapped lifetime of 2.13 ms and secular frequencies of up to 90 MHz. The study confirmed that the motional frequencies scale predictably with the applied RF power and DC quadrupole potential, validating the trap's performance. The authors note that while the lifetime is significantly shorter than that of laser-cooled ions, this is expected for a room-temperature setup lacking active cooling and advanced micromotion compensation.

This work provides a scalable, reproducible, and cost-effective architecture for electron-based quantum computing. By simplifying the fabrication process and eliminating the need for complex assembly, this monolithic approach facilitates the development of cryogenic-compatible traps, which are essential for future experiments involving active cooling and high-fidelity spin readout.