Annual-modulation fingerprint of the axion wind induced sideband triplet in quantum dot spin qubit sensors

We propose a phase-coherent, narrowband magnetometer for searching couplings between axions or axion-like particles (ALPs) and electron spins, using gate-defined silicon quantum-dot spin qubits. With repeated Ramsey echo sequences and dispersive readout, the qubit precession response can be tracked with sub-Hz spectral resolution. The accessible axion mass window is determined using a series of filtering protocols that take into account sensing noise, including readout errors and 1/f noise. We demonstrate clear evidence of sidereal modulation of the signal due to Earth's rotation, while Earth's orbital motion produces an annual amplitude envelope that generates sidebands at fixed frequency spacing pm Ω_oplus around the sidereal component. For axion masses between 1-10 μ{rm eV}, the proposed method covers axion-electron coupling strengths g_ae ranging from 10^-14 to 10^-10. Including both daily and annual modulation patterns in the likelihood analysis enhances the rejection of stationary or instrumental noise. Our results indicate that spin-qubit magnetometry can achieve sensitivities approaching those suggested by astrophysical considerations, providing a complementary, laboratory-based probe of axion-electron interactions. Although we focus on silicon spin-qubit architectures, the approach is broadly applicable to spin-based quantum sensors.