Developing Superconducting Bosonic Qubits in a Planar Low-Loss Architecture

Abstract

Emerging quantum technologies, including quantum computers and quantum simulators, crucially rely on high-quality qubits. However, even state-of-the-art qubits are susceptible to errors caused by noise processes, which impose constraints on the device performance. Standard approaches to quantum error correction aim to suppress these errors by introducing redundancy based on coupling a large number of qubits, which can lead to a significant hardware overhead. In this talk, I will introduce bosonic quantum error correction, which offers an alternative solution by encoding error-protected quantum information into multiple energy levels in a single oscillator. I will discuss our efforts to adapt planar superconducting circuits to the requirements of bosonic qubits, providing the advantage of a smaller footprint compared to bulky three-dimensional microwave cavities. I will compare our results on the fabrication of tantalum coplanar waveguide (CPW) resonators with the current literature. Finally, I will provide an outlook on the prospects of bosonic qubits on superconducting planar devices.