Ultrafast and Electrically Tunable Rabi Frequency in a Germanium Hut Wire Hole Spin Qubit

Area of Science:

• Quantum Computing
• Semiconductor Physics
• Spintronics

Background:

• Germanium (Ge)-based hole spin qubits offer strong spin-orbit interaction (SOI) and rapid operation.
• Controlling qubit properties is essential for developing practical quantum computers.

Purpose of the Study:

• To investigate the electrical tunability of Rabi frequency (fRabi) in a hole spin qubit within a germanium hut wire (HW) double quantum dot (DQD).
• To explore the relationship between fRabi and detuning energy (ϵ) and middle gate voltage (VM).
• To demonstrate the potential for ultrafast qubit operations.

Main Methods:

• Fabrication of a hole spin qubit in a Ge hut wire (HW) double quantum dot (DQD).
• Electrical tuning of the qubit using detuning energy (ϵ) and middle gate voltage (VM).
• Measurement of Rabi frequency (fRabi) under varying electrical conditions.

Main Results:

• Rabi frequency (fRabi) was found to decrease with increasing detuning energy (ϵ).
• Rabi frequency (fRabi) showed a positive correlation with middle gate voltage (VM).
• An ultrafast Rabi frequency exceeding 1.2 GHz was demonstrated, indicating strong SOI.

Conclusions:

• The study successfully demonstrated electrical tunability of Rabi frequency in Ge hole spin qubits.
• The observed tunability is attributed to electric field modulation of SOI and excited state contributions.
• The achieved ultrafast operation speeds highlight the potential of Ge hole spin qubits for quantum computing applications.