Preparing Squeezed Spin States in a Spin–Mechanical Hybrid System with Silicon-Vacancy Centers

An experimentally feasible scheme for preparing the squeezed spin states in a novel spin–mechanical hybrid system is studied. The setup under consideration is realized by a single-crystal diamond waveguide with negatively charged silicon-vacancy (SiV) centers embedded. After studying the strain couplings between the SiV spins and the propagating phonon modes, analyses show that long-range spin–spin interactions can be achieved under large detuning condition. Modeled as an effective one-axis twisting Hamiltonian, these nonlinear spin–spin couplings can steer the system to the squeezed spin states in the practical situations. This proposal may have interesting applications in high-precision metrology and quantum information processing.