Squeezed hole spin qubits in Ge quantum dots with ultrafast gates at low power

TL;DR

This paper proposes a minimal device modification in Ge hole spin qubits that significantly enhances spin-orbit interactions, enabling ultrafast, low-power quantum gate operations with a simple, tunable design.

Contribution

It introduces an asymmetric potential design that boosts spin-orbit interactions without relying on microscopic device details, allowing on-demand control of qubit operations.

Findings

Enhanced spin-orbit interactions by orders of magnitude.

Achieves ultrafast qubit operations in the GHz range.

Design is simple, tunable, and compatible with existing qubit architectures.

Abstract

Hole spin qubits in planar Ge heterostructures are one of the frontrunner platforms for scalable quantum computers. In these systems, the spin-orbit interactions permit efficient all-electric qubit control. We propose a minimal design modification of planar devices that enhances these interactions by orders of magnitude and enables low power ultrafast qubit operations in the GHz range. Our approach is based on an asymmetric potential that strongly squeezes the quantum dot in one direction. This confinement-induced spin-orbit interaction does not rely on microscopic details of the device such as growth direction or strain, and could be turned on and off on demand in state-of-the-art qubits.