Coherent two-state oscillations are observed in numerical simulations of the one-dimensional transverse-longitudinal-field Ising model within false-vacuum decay regimes. Starting from the false vacuum (a nearly fully polarized ferromagnetic state), we show that in moderate-size systems, at resonances $h\approx 2J/n$ (with longitudinal field $h$, transverse field $J$, and an integer $n$), the expected decay can give way to coherent oscillations between the false vacuum and a symmetric resonant state. The oscillation frequency, i.e., the tunneling splitting, is notably observed to exhibit a $\sqrt{L}$ collective enhancement, as confirmed by a Schrieffer-Wolff analysis. In large chains, coherence remains for $n\gtrsim L/2$ due to bubble-size blockade and is robust against stronger transverse fields; for small $n$, long-range interactions can stabilize the oscillations by lifting multibubble degeneracies, establishing a robust many-body coherence mechanism beyond perturbative and finite-size limits.

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• Coherent control
• Cold atoms & matter waves
• Loschmidt echo
• Spin dynamics
• Quantum many-body systems
• Quantum spin models
• Ising model
• Spin lattice models