Operational identifiability of false-vacuum decay rates in the quantum Ising chain

Abstract:Extracting a thermodynamic nucleation rate from finite-time quantum dynamics requires separating observable decay from estimator and finite-size validity. We develop a multilevel identification framework for real-time tensor-network simulations of false-vacuum decay in the one-dimensional quantum Ising chain. Across twelve parameter points, the same coherent two-kink amplitudes semi-quantitatively predict both infinite-chain survival and magnetization dynamics: the survival coefficient has a median lattice-to-theory ratio of 0.896, while the magnetization-area slope ratios span 0.767--0.931. By contrast, the microscopic nearest-neighbour bond response is coherence dominated: vacuum--pair coherence contributes 60.0--81.5% across seven points with matched bond-dimension control, while substantial late-window slope discrepancies remain that cannot be removed by a scalar normalization. The analysis establishes finite-time survival and magnetization benchmarks and identifies the additional finite-size and branch-validation requirements for a bulk thermodynamic rate interpretation. Within the two-kink model and under the adopted common normalization, the lattice-resolved WKB action gives a median fixed-prefactor rate discrepancy of 4.13% from the coherent-bubble spectral calculation. These results distinguish finite-time lattice--theory consistency from the additional observable and finite-size evidence required to identify a thermodynamic nucleation rate.

19 pages, 4 figures. Main text condensed with details moved to supplementary material. Submitted to $\textit{Journal of Physics: Condensed Matter}$

Statistical Mechanics (cond-mat.stat-mech); Quantum Physics (quant-ph)

arXiv:2608.11339 [cond-mat.stat-mech]

(or arXiv:2608.11339v2 [cond-mat.stat-mech] for this version)

https://doi.org/10.48550/arXiv.2608.11339 Focus to learn more arXiv-issued DOI via DataCite

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