Sweet-spot operation of a germanium hole spin qubit with highly anisotropic noise sensitivity

Abstract

Spin qubits defined by valence band hole states comprise an attractive candidate for quantum information processing due to their inherent coupling to electric fields enabling fast and scalable qubit control. In particular, heavy holes in germanium have shown great promise, with recent demonstrations of fast and high-fidelity qubit operations. However, the mechanisms and anisotropies that underlie qubit driving and decoherence are still mostly unclear. Here, we report on the highly anisotropic heavy-hole $g$-tensor and its dependence on electric fields, allowing us to relate both qubit driving and decoherence to an electric modulation of the $g$-tensor. We also confirm the predicted Ising-type hyperfine interaction but show that qubit coherence is ultimately limited by $1/f$ charge noise. Finally, we operate the qubit at low magnetic field and measure a dephasing time of $T_2^{\ast }=9.2$ $\mu$s, while maintaining a single-qubit gate fidelity of 99.94 %, that remains well above 99 % at an operation temperature T>1 K. This understanding of qubit driving and decoherence mechanisms are key for the design and operation of scalable and highly coherent hole qubit arrays.

Main text: 12 pages, 6 figures, 50+9 references. Supplementary information is included at the end: 9 pages, 11 figures

References in corpus (20)

• An addressable quantum dot qubit with fault-tolerant control fidelity
• How to Enhance Dephasing Time in Superconducting Qubits
• A four-qubit germanium quantum processor
• Spin decoherence of a heavy hole coupled to nuclear spins in a quantum dot
• Electron Spin Dephasing due to Hyperfine Interactions with a Nuclear Spin Bath
• Exact Results on Dynamical Decoupling by $\pi$-Pulses in Quantum Information Processes
• Pure quantum dephasing of a solid state electron spin qubit in a large nuclear spin bath coupled by long-range hyperfine-mediated interactions
• A singlet triplet hole spin qubit in planar Ge
• A single hole spin with enhanced coherence in natural silicon
• Squeezed hole spin qubits in Ge quantum dots with ultrafast gates at low power
• Simultaneous single-qubit driving of semiconductor spin qubits at the fault-tolerant threshold
• Spin Orientation of Holes in Quantum Wells
• Dynamics of hole singlet triplet qubits with large g-factor differences
• Hole spin driving by strain-induced spin-orbit interactions
• Electrical control of the $g$-tensor of a single hole in a silicon MOS quantum dot
• Lightly-strained germanium quantum wells with hole mobility exceeding one million
• Hole spin manipulation in inhomogeneous and non-separable electric fields
• First-principles hyperfine tensors for electrons and holes in GaAs and silicon
• Anisotropic g-Factor and Spin-Orbit Field in a Ge Hut Wire Double Quantum Dot
• Shared control of a 16 semiconductor quantum dot crossbar array

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