Additive Manufacturing of Scalable 3D Resonators

This proposal is submitted in response to the SBIR/STTR Office of Science related to Quantum Information Science (QIS) Supporting Technologies. There is the need for fabrication techniques for scalable 3D Superconducting Radio Frequency (SRF) Structures for Quantum Information Systems. In this proposal we will develop an additive manufacturing approach to developing superconducting 3D microwave resonators and quantum memories for QIS. Optimized superconducting 3D microwave resonators are needed for shielding Josephson junction qubits at low temperatures. The need is for the highest possible Q-factor to improve the coherence time for cavity-qubit systems, to minimize de-coherence. Here we propose to use 3-D printing of Nb metal to form the 3-D resonator. This approach offers the simultaneous advantages of quick prototyping, ease of change of resonator design, and scalability, both in terms of size and in terms of multiple unit arrays. The process may potentially offer the advantage of compatibility with other fabrication processes needed for Q-bit formation, and may point the way towards integrated fabrication of qubit and resonator system. We will explore resonators made using a powder bed fusion approach with both e-beam and laser melting alternatives available. Material quality, surface quality, and Q-factor will be explored for simple geometries in Phase I along with design of optimized resonator shapes. We will focus on Nb materials. A route which can directly form Nb based SRF microwave shielding cavities would be of direct benefit to QIS qubit shielding. This proposed work has potential to impact the development of practical quantum computing, in terms of improving the potential for scale-up of quantum computing circuits to practical level devices. The potential applications of quantum computers are vast, and difficult to project. However, they have strong potential to influence many aspects of computing for science, for security, and eventually for commercial purposes. Applications of quantum computing are likely to be either in the area of security or science. The first applications of quantum computing will almost certainly be scientific computation where simulations may be the first application, in the long run, quantum computing has the potential to change the face of computation relevant to vast parts of the economy.