Low charge noise in atom qubits in silicon*

Despite electron spins in silicon offering a competitive, scalable quantum computing platform two-qubit gate fidelities to date have fallen short of the 99% threshold required for error-corrected processors. In the past few years there has been a growing realization that the critical obstacle in meeting this threshold is charge noise, which results in J fluctuations during the two-qubit gate operation, limiting the gate fidelity. Here, we show a significantly reduced magnitude of charge noise in all-epitaxial, precision placed phosphorus atom-based platform, in which the qubits are naturally separated from surfaces and interface states. We perform charge noise measurements using both the charge sensor and the qubits themselves. We find a consistent charge noise spectrum over 4 frequency decades in the sub-Hz frequency regime, with the noise level of S₀ = 0.0088 ± 0.0004 µeV²/Hz, one order of magnitude lower than that reported in other systems. We believe that studying the origins of charge noise and its spectrum in our system will enable the design of noise resilient multi-qubit devices and protocols.