Comprehensive Materials and Morphologies Study of Ion Traps (COMMIT) for Scalable Quantum Computation

Abstract

Abstract : Trapped ion systems, are extremely promising for large-scale quantum computation, but face a vexing problem, with motional quantum states decohering as trap sizes are reduced, far more rapidly than expected due to Johnson noise. This heating issue leads to low quantum logic gate fidelities. Furthermore, integration with fiber optic and CMOS control technologies introduces new materials, typically dielectrics and semiconductors, known to cause high heating when positioned too close to ions. This project developed and deployed a unique cryogenic ion trap system for fast test & evaluation of ion heating rates, characterizing surface-electrode ion traps made of copper, gold, silver, aluminum, nickel, niobium, and niobium nitride traps. These trap materials were fabricated using a wide variety of techniques, including e-beam deposition, electroplating, and sputtering. And traps were operated under a wide range of conditions, including temperatures varying from 6K to room temperature. Measurements of the superconducting traps indicate that noise sources are likely on the surface, instead of being due to sub-surface defects. Overall, results show a significant reduction of heating rates, by up to three orders of magnitude, for certain materials, when operated at 6K, versus at room-temperature. This offers a promising direction for advancing large-scale fault-tolerant quantum computation with microfabricated ion trap systems.