Many-Body Quantum Lock-In Amplifier

Achieving high-precision detection of time-dependent signals in noisy environment is a ubiquitous issue physics and critical task metrology. Lock-in amplifiers are detectors that can extract alternating with known carrier frequency from an extremely environment. Here, we present protocol for achieving entanglement-enhanced lock-in amplifier via empoying many-body quantum interferometry periodic multiple pulses. Generally, includes three stages: initialization, interrogation, readout. The be achieved adding suitable multiple-$\pi$-pulse sequence during the interrogation. Our analytical results show that, by selecting input states readout operations, amplitude unknown field simultaneously extracted population measurements. In particular, if spin cat apply interaction-based measurement precisions both approach Heisenberg limit. Moreover, our robust against extreme stochastic noises. study may point out new direction measuring systems, provides feasible way Heisenberg-limited signals.