Parasitic-free gate: A protected switch between idle and entangled states

Abstract

We propose a protected 2-qubit gate composed of two sub-gates that switches between idling and entangling modes. These sub-gates are separated by a large energy barrier. In superconducting circuits, this gate is derived by harnessing microwave driving and coupling modulation. The idle mode decouples qubits and leaves them with highly localized wave functions. The entangled mode, however, makes them interact in absence of the adversarial ZZ interactions. Our theoretical results show that this gate is a promising way to switch on and off a fast and high fidelity 2-qubit interaction.