Probing Dynamics of Multi-atom Quantum Coherence in Rubidium Vapors

The temperature-dependent decoherence dynamics of multi-atom coherence states in rubidium-87 vapor are studied using multi-quantum excitation spectroscopy. By selectively probing single-quantum (1Q), double-quantum (2Q), and triple-quantum (3Q) coherence pathways, we measure coherence lifetimes and decay mechanisms across a broad range of thermal conditions (30–150 °C). Extended scans of the interpulse delay T provide high-resolution spectra that resolve hyperfine splittings in the ground state, corresponding to 6.8 GHz, 13.6 GHz, and 20 GHz for 1Q, 2Q, and 3Q, respectively. By studying these dynamics at different temperatures, we reveal the influence of thermal motion, collisional broadening, and many-body interactions on coherence decay. Higher-order coherence pathways exhibit faster decay, consistent with many-body interaction effects and collisional broadening. These physical limits on coherence in thermally driven atomic ensembles provide quantitative benchmarks for modeling multi-atom dynamics and offer practical insights for developing robust quantum control protocols and quantum information processing schemes under realistic thermal environments.