Probing high-frequency gravitational waves with entangled vibrational qubits in linear Paul traps

Abstract

This work investigates the use of linear Paul traps as quantum sensors for detecting megahertz gravitational waves. Single-ion configurations exploit graviton-photon conversion in the presence of external magnetic fields, while two-ion systems use relative-motion excitations, which do not require magnets, to distinguish gravitational waves from axion dark matter. Furthermore, we show that entanglement of $N$ vibrational qubits enhances the signal probability by a factor of $N^2$, improving sensitivity beyond the standard quantum limit.