$\mathcal{PT}$ Symmetric Hamiltonian Model and Exactly Solvable Potentials

Abstract

Searching for non-Hermitian (parity-time)$\mathcal{PT}$-symmetric Hamiltonians \cite{bender} with real spectra has been acquiring much interest for fourteen years. In this article, we have introduced a $\mathcal{PT}$ symmetric non-Hermitian Hamiltonian model which is given as $\hat{\mathcal{H}}=ω(\hat{b}^\dagger\hat{b}+\frac{1}{2})+ α(\hat{b}^{2}-(\hat{b}^\dagger)^{2})$ where $ω$ and $α$ are real constants, $\hat{b}$ and $\hat{b^\dagger}$ are first order differential operators. Moreover, Pseudo-Hermiticity that is a generalization of $\mathcal{PT}$ symmetry has been attracting a growing interest \cite{mos}. Because the Hamiltonian $\mathcal{H}$ is pseudo-Hermitian, we have obtained the Hermitian equivalent of $\mathcal{H}$ which is in Sturm- Liouville form leads to exactly solvable potential models which are effective screened potential and hyperbolic Rosen-Morse II potential. $\mathcal{H}$ is called pseudo-Hermitian, if there exists a Hermitian and invertible operator $η$ satisfying $\mathcal{H^\dagger}=η\mathcal{H} η^{-1}$. For the Hermitian Hamiltonian $h$, one can write $h=ρ\mathcal{H} ρ^{-1}$ where $ρ=\sqrtη$ is unitary. Using this $ρ$ we have obtained a physical Hamiltonian $h$ for each case. Then, the Schrödinger equation is solved exactly using Shape Invariance method of Supersymmetric Quantum Mechanics \cite{susy1}. Mapping function $ρ$ is obtained for each potential case.

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