Hybrid method of generating spin-squeezed states for quantum-enhanced atom interferometry

We introduce a spin-squeezing technique that is a hybrid of two well-established spin-squeezing techniques, quantum nondemolition measurement (QND), and one-axis twisting (OAT). This hybrid method aims to improve spin-squeezing over what is currently achievable using QND and OAT. In practical situations, the strength of both the QND and OAT interactions is limited. We find that, in these situations, the hybrid scheme performed considerably better than either OAT or QND used in isolation. As QND and OAT have both been realized experimentally, this technique could be implemented in current atom interferometry setups with only minor modifications to the experiment.