This project aims to realize a new platform for quantum computing based on trapped ions. Quantum computing is attracting vast attention due to its potential to solve problems which are intractable on devices which only use classical physics. However expected scales for useful devices require many thousands of qubits. While trapped ions are a promising approach towards this goal, systems today use up to 50 qubits, trapped in systems where radio-freqeency fields are used to confine ions. This creates a number of problems for scaling, including heat dissipation, a lack of natural paths to 2-dimensional arrays, and a constant calibration challenge due to drifts in electric fields. This project aims to make a new path for trapped-ion quantum computing by replacing the radio-frequency field with a large static magnetic field (Penning trap), and thus avoiding the aforementioned problems. While Penning traps are used for precision spectroscopy and quantum simulation, these are all devices with centimetre scale electrodes, not suited for quantum computing. This project pursues microfabricated electrode structures, allowing arrays of Penning traps to be developed. This constitutes a new Quantum CCD architecture for ion trap quantum computing, which should open a clear path to useful quantum computers.
The project has been successful in realizing the first micro-fabricated surface-electrode Penning trap, in which beryllium ions were trapped initially 150 microns above the surface of the electrodes. We have been able to perform full quantum state control of both motional and internal states of the ions in this system, as well as demonstrating the first two-qubit gates between two ions in a Penning trap. We have demonstrated 3-dimensional translation of the ion above the chip surface, and used this to implement a scanning ion sensor for probing both static as well as time-varying electric and magnetic fields above the trap surface. The work constitutes establishing the foundations of the Penning Quantum CCD architecture for quantum computing, which will be pursued both academically as well as by our new start-up company ZuriQ, established in May 2024.
