Flopping-mode electron dipole spin resonance in the strong-driving regime

TL;DR

This paper explores a novel strong-driving flopping-mode for electron dipole spin resonance in double quantum dots, aiming to improve control fidelity and speed while addressing challenges posed by silicon's valley degeneracy.

Contribution

It proposes operating the flopping-mode in the strong-driving regime and demonstrates potential fidelity improvements through simulations, considering silicon's valley effects.

Findings

Strong-driving regime increases Rabi frequency to 60 MHz

Charge noise impact reduced by over two orders of magnitude

Valley degeneracy complicates strong-driving operation in silicon

Abstract

Achieving high fidelity control of spin qubits with conventional electron dipole spin resonance (EDSR) requires large magnetic field gradients of about 1 mT/nm, which also couple the qubit to charge noise, and large drive amplitudes of order 1 mV. The flopping-mode is an alternative method to drive EDSR of an electron in a double quantum dot, where the large displacement between both dots increases the driving efficiency. We propose to operate the flopping-mode in the strong-driving regime to use the full magnetic field difference between the two dots. In simulations, the reduced required magnetic field gradients suppress the infidelity contribution of charge noise by more than two orders of magnitude, while providing Rabi frequencies of up to 60 MHz. However, the near degeneracy of the conduction band in silicon introduces a valley degree of freedom that can degrade the performance of the strong-driving mode. This necessitates a valley-dependent pulse optimization and makes operation to the strong-driving regime questionable.