Entanglement-enhanced quantum lock-in detection achieving Heisenberg scaling.

ABSTRACT: Quantum lock-in detection (QLID) is a powerful technique for extracting weak oscillating signals within noise. While entanglement may enhance measurement precision beyond the standard quantum limit (SQL), its integration with QLID is still an experimental challenge. Here we report the first experimental realization of entanglement-enhanced QLID using two trapped ⁴⁰Ca⁺ ions. We prepare a Greenberger-Horne-Zeilinger (GHZ) state using a Mϕlmer-Sϕrensen gate and then apply periodic multipulse sequences to execute QLID. Using the GHZ state, the measurement precision approaches the Heisenberg limit (Δω ∝ N^-1), surpassing the SQL (Δω ∝ N^-1/2) achievable with non-entangled states. Notably, QLID achieves a superior inverse-quadratic temporal scaling (Δω ∝

SUBMITTER: Zhang JW 

PROVIDER: S-EPMC12775457 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature