Initial Design of a W-band Superconducting Kinetic Inductance Qubit (Kineticon)

TL;DR

This paper introduces a novel superconducting kinetic inductance qubit, called Kineticon, operating at W-band frequencies, which could enable higher temperature operation and scalable multiplexing in quantum computing.

Contribution

It presents the initial design and simulation of a W-band Kineticon qubit using high-gap superconductor NbTiN, expanding qubit operation into millimeter-wave frequencies.

Findings

Design and simulation of a W-band Kineticon qubit

Analysis of electromagnetic field distributions in the cavity

Potential for higher temperature and multiplexed quantum computing

Abstract

Superconducting qubits are widely used in quantum computing research and industry. We describe a superconducting kinetic inductance qubit (and introduce the term Kineticon to describe it) operating at W-band frequencies with a nonlinear nanowire section that provides the anharmonicity required for two distinct quantum energy states. Operating the qubits at higher frequencies may relax the dilution refrigerator temperature requirements for these devices and paves the path for multiplexing a large number of qubits. Millimeter-wave operation requires superconductors with relatively high $T_c$, which implies high gap frequency, 2$\Delta/h$, beyond which photons break Cooper pairs. For example, NbTiN with $T_c =15\,\text{K}$ has a gap frequency near 1.4 THz, which is much higher than that of aluminum (90 GHz), allowing for operation throughout the millimeter-wave band. Here we describe a design and simulation of a W-band Kineticon qubit embedded in a 3-D cavity. We perform classical electromagnetic calculations of the resulting field distributions.