Semiclassical Calculation of the C Operator in PT-Symmetric Quantum Mechanics

TL;DR

This paper develops a semiclassical method to compute the C operator in PT-symmetric quantum mechanics for noncubic Hamiltonians, extending previous perturbative approaches to more complex systems.

Contribution

It introduces a nonperturbative semiclassical approach to calculate the C operator for a broader class of PT-symmetric Hamiltonians, beyond cubic cases.

Findings

Successfully applied semiclassical methods to noncubic Hamiltonians

Extended the calculation of the C operator beyond perturbation theory

Provided a framework for analyzing PT-symmetric systems with complex potentials

Abstract

To determine the Hilbert space and inner product for a quantum theory defined by a non-Hermitian $\mathcal{PT}$-symmetric Hamiltonian $H$, it is necessary to construct a new time-independent observable operator called $C$. It has recently been shown that for the {\it cubic} $\mathcal{PT}$-symmetric Hamiltonian $H=p^2+ x^2+i\epsilon x^3$ one can obtain $\mathcal{C}$ as a perturbation expansion in powers of $\epsilon$. This paper considers the more difficult case of noncubic Hamiltonians of the form $H=p^2+x^2(ix)^\delta$ ($\delta\geq0$). For these Hamiltonians it is shown how to calculate $\mathcal{C}$ by using nonperturbative semiclassical methods.