Measuring pulse heating in Si quantum dots with individual two-level fluctuators

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 Si/SiGe quantum dots. We find that the TLFs are susceptible to pulse heating. The amount of heating depends on the pulse amplitude and frequency, but not on the distance between the pulsed gate and the TLF. The amount of heating also generally depends on the idling voltage of the gate, suggesting that electrons accumulated under the gates contribute to the heating. Our results indicate a possible mechanism for the heating and potential mitigation strategies.