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QI: Fachverband Quanteninformation

QI 2: Semiconductor Qubits (joint session QI/HL)

QI 2.7: Vortrag

Montag, 18. März 2024, 11:45–12:00, HFT-FT 131

Dynamical sweetspots in driven germanium double quantum dot spin qubits — •Yaser Hajati and Guido Burkard — Konstanz University, Konstanz, Germany

In recent years, significant strides have been made in advancing hole-spin qubits based on semiconductor quantum dots, particularly in germanium (Ge). Hole spins in Ge quantum dots can leverage the strong spin-orbit coupling compared to silicon, potentially enabling fast and reliable qubit operations. Our study focuses on exploring the use of a periodic drive field to engineer the properties of Ge quantum-dot based qubits amidst charge noise. Specifically, we investigated the Rabi frequency of a hole qubit experiencing detuning driving in a planar Ge double quantum dot, focusing on the single-hole flopping mode with spin-orbit interaction. Our findings indicate that the Rabi frequency linked to a hole within a planar double quantum dot, driven on resonance, exhibits an inverse correlation with detuning energy while demonstrating a positive correlation with driving frequency, Zeeman field strength, and spin-orbit coupling. Furthermore, through strategic modulation of the drive frequencies slightly off resonance, we effectively mitigated the impact of charge noise. This modulation significantly boosted the fidelity of quantum gates when manipulating the qubit within specific ranges of drive frequencies and detuning. Importantly, our study shows that fidelity improvements at dynamic sweet spots exceed those achievable by solely adjusting drive frequency and detuning. Discovering these spots holds potential for enhancing quantum gate reliability in Ge quantum dot-based computing.

Keywords: Spin qubit; Germanium; flopping mode; sweet spot