Design and Performance Analysis of Hexagonal Transmon Qubit in a Superconducting Circuit

Superconducting quantum bits (qubits) are considered as promising candidates to serve as a platform for a quantum information processor. For the realization of practical quantum computing devices, scalable designs and long lifetimes of qubits are required. In this paper, we present simulation results of “hexagonal” transmon qubit in a superconducting coplanar waveguide (CPW) resonator. We conducted finite-element method simulations considering dielectric losses including the two-level system (TLS) loss to evaluate the performance of the qubit in a practical sense. Then, key parameters of a qubit in superconducting circuits - including lifetime, coupling strength, and energy levels are estimated by the black-box quantization method or by solving circuit quantum-electrodynamics (cQED). Finally, the geometric features and key parameters of the qubit are suggested for typical quantum information processing applications.