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Nonlinearity and quantum metrology in the double-Morse potential
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DOI:10.1140/epjqt/s40507-026-00547-2.png)
Abstract
En 中文
We address the nonlinear properties of the double-Morse potential as a resource for single-mode quantum states due to its double-well structure and anharmonicity. We obtain analytical expressions for the ground-state wavefunction and the corresponding ground-state energy, using the asymmetry (width) parameter α as the primary control parameter. We then assess non-Gaussianity and nonclassicality as quantitative signatures of nonlinearity and quantumness, and we find that both increase monotonically with α. Furthermore, we analyze the metrological performance of the model for estimating the structural parameter α. By evaluating the corresponding Fisher information, we show that position measurements are optimal and can saturate the Cramér–Rao bound. In particular, the estimation of α is most precise in the shallow-well regime, where the quantum Fisher information is largest. For deep wells, enhanced sensitivity is instead obtained for the reparameterized control variable $A=2e^{-\alpha x_{0}}$, provided that $x_{0}$ is independently calibrated. These results establish the double-Morse potential as a controllable source of non-Gaussianity and nonclassicality, with a metrological behavior that depends on the chosen estimation parameter. We highlight possible applications of this model in quantum sensing, continuous-variable quantum information, and quantum simulation.
Keywords:
Nonclassicality
Nonlinearity
Quantum information
Entanglement generation
Fisher information
Journal
IF:
5.6
Papers:
517
Citations:
1.1K
