To encode quantum information in semiconductor spin qubits, voltage pulses are necessary for initialization, gate operation, and readout. However, these pulses dissipate heat, shifting spin-qubit frequencies and reducing gate fidelities. The cause of this pulse heating in quantum dot devices is unknown. Here, we measure pulse heating using charged two-level fluctuators (TLFs) in $\mathrm{Si}$/($\mathrm{Si}$-$\mathrm{Ge}$) quantum dots. Specifically, we observe that voltage pulses on nearby gates tend to increase TLF switching rates and occupation biases. The amount of heating depends on the pulse amplitude and frequency, but not on the distance between the pulsed gates and the TLFs. The amount of heating also generally depends on the idling voltage of the pulsed gates, suggesting that electrons accumulated under or near the gates contribute to the heating. We hypothesize that reducing the area of the gates with electrons nearby could mitigate the heating.

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• Heat transfer
• Open quantum systems & decoherence
• Quantum information with solid state qubits
• Elemental semiconductors
• Quantum dots
• Microwave techniques
• Thermometry
• Two-level models