Ultrafast Quantum Gates in Circuit QED

Understand

We present a method of implementing ultrafast two-qubit gates valid for the ultrastrong coupling (USC) and deep strong coupling (DSC) regimes of light-matter interaction, considering state-of-the-art circuit quantum electrodynamics (QED) technology.

• Our proposal includes a suitable qubit architecture and is based on a four-step sequential displacement of an intracavity mode, operating at a time proportional to the inverse of the resonator frequency.
• Through ab initio calculations, we show that these quantum gates can be performed at subnanosecond time scales, while keeping the fidelity above 99%.