Curator's Take
This article introduces the ferroelectric transmon (FEmon), a superconducting qubit that adds a nonlinear ferroelectric capacitor in parallel with the Josephson junction to boost anharmonicity without leaving the charge‑noise‑insensitive regime. By giving designers an extra knob for shaping the energy spectrum, the FEmon could reconcile the long‑standing trade‑off between fast gate speeds and low decoherence that has limited conventional transmons and motivated alternatives such as fluxonium and 3D cavities. If the material integration challenges of ferroelectric thin films can be mastered, the approach promises a straightforward path to higher‑fidelity operations on existing superconducting platforms.
— Mark Eatherly
Summary
Superconducting qubits are a leading platform for quantum computing. However, simultaneously achieving low noise sensitivity to suppress decoherence and sufficient anharmonicity to enable fast gate operations remains a central challenge. Here, we introduce the concept of the ferroelectric transmon (FEmon), in which the Josephson junction is shunted by a ferroelectric, or incipient ferroelectric, capacitor. We show, in particular, that the nonlinear ferroelectric response of the capacitor provides an additional degree of freedom for optimizing qubit anharmonicity while preserving operation in the charge-noise-insensitive regime.