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arXiv · 1111.0484

N-site-lattice analogues of $V(x)=i x^3$

Miloslav Znojil
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Abstract

Two discrete N-level alternatives to the popular imaginary cubic oscillator are proposed and studied. In a certain domain ${\cal D}$ of parameters $a$ and $z$ of the model, the spectrum of energies is shown real (i.e., potentially, observable) and the unitarity of the evolution is shown mediated by the construction of a (non-unique) physical, ad hoc Hilbert space endowed with a nontrivial, Hamiltonian-dependent inner-product metric $\Theta$. Beyond ${\cal D}$ the complex-energy curves are shown to form a "Fibonacci-numbered" geometric pattern and/or a "topologically complete" set of spectral loci. The dynamics-determining construction of the set of the eligible metrics is shown tractable by a combination of the computer-assisted algebra with the perturbation and extrapolation techniques. Confirming the expectation that for the local potentials the effect of the metric cannot be short-ranged.

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BibTeXRIS

Miloslav Znojil. 2011-11-02. N-site-lattice analogues of $V(x)=i x^3$. https://doi.org/10.1016/j.aop.2011.12.009

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