Three-axis Active Magnetic Compensation with Spatial Feedforward Matrix Decoupling and Hysteresis PI Regulation for Suppressing Zeeman Decoherence of Cold Atom Quantum Memories
The work proposes a new method to keep magnetic fields near zero in cold atom quantum memories, which is crucial for preventing decoherence. They combine a physical coil frame, an inverse matrix for decoupling crosstalk, and a dual-threshold PI controller to actively suppress magnetic interference. Experiments show this architecture achieves very low residual fields (down to 0.112 microtesla) and excellent long-term stability.