Loss Mechanisms in Superconducting Quantum Transmission Line Metamaterials

Superconducting quantum bits (qubits) coupled with resonators are widely utilized for applications in quantum computing. Efforts are under way to scale up the numbers of qubits, but there are many recurring issues of dielectric loss of substrate materials, two level systems, and quasi-particles loss, all leading to decoherence of superconducting qubits. In order to understand different loss mechanisms, our group is fabricating many high-quality aluminum half wavelength transmission line resonators by e-beam deposition and photo-lithography methods. Through the investigation of power dependence and temperature dependence of these transmission line resonators, and comparison with different theoretical models, the dominant loss mechanism in our half wavelength transmission line can be identified. This transmission line will later host many flux qubits to study the collective behavior of a quantum metamaterial system