Ultrafast coherent control of a hole spin qubit in a germanium quantum dot

TL;DR

This paper demonstrates ultrafast coherent control of a hole spin qubit in germanium quantum dots, achieving record Rabi frequencies due to strong spin-orbit interaction, advancing the prospects for scalable quantum computing.

Contribution

It reports the first ultrafast single-spin manipulation in germanium hole quantum dots with a Rabi frequency over 540 MHz, leveraging strong spin-orbit coupling for rapid control.

Findings

Achieved Rabi frequency >540 MHz in germanium hole quantum dots.

Demonstrated rapid, all-electrical coherent control of hole spin qubits.

Showed potential for scalable quantum information processing with ultrafast control.

Abstract

Operation speed and coherence time are two core measures for the viability of a qubit. Strong spin-orbit interaction (SOI) and relatively weak hyperfine interaction make holes in germanium (Ge) intriguing candidates for spin qubits with rapid, all-electrical coherent control. Here we report ultrafast single-spin manipulation in a hole-based double quantum dot in a germanium hut wire (GHW). Mediated by the strong SOI, a Rabi frequency exceeding 540 MHz is observed at a magnetic field of 100 mT, setting a record for ultrafast spin qubit control in semiconductor systems. We demonstrate that the strong SOI of heavy holes (HHs) in our GHW, characterized by a very short spin-orbit length of 1.5 nm, enables the rapid gate operations we accomplish. Our results demonstrate the potential of ultrafast coherent control of hole spin qubits to meet the requirement of DiVincenzo's criteria for a scalable quantum information processor.