Two-Level-Fluctuators as a source of 1/f noise and quantum gate errors in spin qubits

Electrons confined in gate defined quantum dots are promising candidates for qubit implementations. Long coherence times have been achieved by migrating to isotopically purified Silicon platforms in which nuclear hyperfine interactions are minimized. However, charge noise still remains a limiting factor for the spin qubits' coherence and quantum gate fidelities. Noise spectral densities measured via charge sensors and decoherence behaviour of qubits show 1/f -like trends, which are characteristic of charge noise. In this work we gain insights on the charge noise profile by simulating the electrostatic fluctuations introduced by different Two-Level-Fluctuators (TLFs). The result is then compared to experimentally measured noise spectral densities measured by Single Electron Transistors (SET). We further assess the sensitivity of one- and two- qubit quantum gates to the charge fluctuations introduced by the aforementioned TLFs based on combining electrostatic models with configuration interaction and quantum dynamics calculations. The microscopic treatment of individual TLFs presented here offers an insight on the nature of the charge noise sources in addition to enabling realistic incorporation of charge noise in quantum mechanical models of spin qubit devices.