Signal amplification in a solid-state quantum sensor via asymmetric time-reversal of many-body dynamics

Electronic spins of nitrogen vacancy (NV) centers in diamond constitute a promising system for micro- and nano-scale magnetic sensing, due to their operation under ambient conditions, ease of placing in close proximity to sensing targets, and biological compatibility. At high density, the electronic spins interact through dipolar coupling, which typically limits but can also potentially enhance sensing performance. Here, we demonstrate sensing signal amplification in a two-dimensional ensemble of NV centers at room temperature, enabled by time-reversed two-axis-twisting interactions, engineered through dynamical control of the quantization axis and Floquet engineering. Strikingly, we observe that the optimal amplification occurs when the backward evolution time equals twice the forward evolution time. These observations can be understood as resulting from an underlying time-reversed mirror symmetry of the microscopic dynamics, providing key insights to signal amplification and opening the door towards entanglement enhanced sensing in the solid state under ambient conditions.