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We perform a perturbative calculation of the physical observables, in particular pseudo-Hermitian position and momentum operators, the equivalent Hermitian Hamiltonian operator, and the classical Hamiltonian for the PT-symmetric cubic…

Quantum Physics · Physics 2011-07-19 Ali Mostafazadeh

Some PT-symmetric non-hermitean Hamiltonians have only real eigenvalues. There is numerical evidence that the associated PT-invariant energy eigenstates satisfy an unconventional completeness relation. An ad hoc scalar product among the…

Quantum Physics · Physics 2009-11-10 Stefan Weigert

We introduce a very simple, exactly solvable PT-symmetric non-Hermitian model with real spectrum, and derive a closed formula for the metric operator which relates the problem to a Hermitian one.

Mathematical Physics · Physics 2009-11-11 D. Krejcirik , H. Bila , M. Znojil

We introduce a relativistic version of the non-self-adjoint operator obtained by a dilation analytic transformation of the quantum harmonic oscillator. While the spectrum is real and discrete, we show that the eigenfunctions do not form a…

Spectral Theory · Mathematics 2025-08-19 A. Balmaseda , D. Krejcirik , J. M. Pérez-Pardo

It is established that a PT-symmetric elliptic quadratic differential operator with real spectrum is similar to a self-adjoint operator precisely when the associated fundamental matrix has no Jordan blocks.

Mathematical Physics · Physics 2015-06-04 Emanuela Caliceti , Sandro Graffi , Michael Hitrik , Johannes Sjoestrand

We show that a quantum system possessing an exact antilinear symmetry, in particular PT-symmetry, is equivalent to a quantum system having a Hermitian Hamiltonian. We construct the unitary operator relating an arbitrary non-Hermitian…

Quantum Physics · Physics 2008-11-26 Ali Mostafazadeh

We treat the quantum dynamics of a harmonic oscillator as well as its inverted counterpart in the Schr\"odinger picture. Generally in the most papers of the literature, the inverted harmonic oscillator is formally obtained from the harmonic…

Quantum Physics · Physics 2022-04-25 Nadjat Amaouche , Ishak Bouguerche , Rahma Zerimeche , Mustapha Maamache

We investigate properties of the most general PT-symmetric non-Hermitian Hamiltonian of cubic order in the annihilation and creation operators as a ten parameter family. For various choices of the parameters we systematically construct an…

Quantum Physics · Physics 2008-11-21 Paulo E. G. Assis , Andreas Fring

Given a Hilbert space operator $T$, the level sets of function $\Psi_T(z)=\|(T-z)^{-1}\|^{-1}$ determine the so-called pseudospectra of $T$. We set $\Psi_T$ to be zero on the spectrum of $T$. After giving some elementary properties of…

Functional Analysis · Mathematics 2016-10-18 Avijit Pal , Dmitry V. Yakubovich

We reflect real spectra of new logarithmic model PT-symmetry operators with singular and non-singular in nature. We also notice that iso-spectral nature between inverted and non-inverted logarithmic PT-symmetric potentials. Present…

Quantum Physics · Physics 2023-08-09 Biswanath Rath , Rabab Jarrar , Hussein Shanak , Jihad Asad , Rania Wannan

Relativistic massive bosons with spin one are considered in several quantization schemes. In all of them the system is shown described by a non-Hermitian Hamiltonian and helicity operator. Constructively we show that in all of the…

High Energy Physics - Theory · Physics 2008-11-26 Jaroslav Smejkal , Vit Jakubsky , Miloslav Znojil

We propose giving the mathematical concept of the pseudospectrum a central role in quantum mechanics with non-Hermitian operators. We relate pseudospectral properties to quasi-Hermiticity, similarity to self-adjoint operators, and basis…

Spectral Theory · Mathematics 2015-11-30 D. Krejcirik , P. Siegl , M. Tater , J. Viola

A general strategy is provided to identify the most general metric for diagonalizable pseudo-Hermitian and anti-pseudo-Hermitian Hamilton operators represented by two-dimensional matrices. It is investigated how a permutation of the…

Quantum Physics · Physics 2021-02-17 Frieder Kleefeld

We provide a mathematical framework for PT-symmetric quantum theory, which is applicable irrespective of whether a system is defined on R or a complex contour, whether PT symmetry is unbroken, and so on. The linear space in which…

High Energy Physics - Theory · Physics 2008-11-26 Toshiaki Tanaka

We prove that any symmetric Hamiltonian that is a quadratic function of the coordinates and momenta has a pseudo-Hermitian adjoint or regular matrix representation. The eigenvalues of the latter matrix are the natural frequencies of the…

Quantum Physics · Physics 2016-05-04 Francisco M Fernández

For a specific exactly solvable 2 by 2 matrix model with a PT-symmetric Hamiltonian possessing a real spectrum, we construct all the eligible physical metrics and show that none of them admits a factorization CP in terms of an involutive…

Quantum Physics · Physics 2009-11-13 Miloslav Znojil , Hendrik B. Geyer

The Hamiltonian for quantum electrodynamics becomes non-Hermitian if the unrenormalized electric charge $e$ is taken to be imaginary. However, if one also specifies that the potential $A^\mu$ in such a theory transforms as a pseudovector…

High Energy Physics - Theory · Physics 2011-07-19 Carl M. Bender , Ines Cavero-Pelaez , Kimball A. Milton , K. V. Shajesh

The quantum measurement axiom dictates that physical observables and in particular the Hamiltonian must be diagonalizable and have a real spectrum. For a time-independent Hamiltonian (with a discrete spectrum) these conditions ensure the…

Quantum Physics · Physics 2009-11-13 Ali Mostafazadeh

Examples are given of non-Hermitian Hamiltonian operators which have a real spectrum. Some of the investigated operators are expressed in terms of the generators of the Weil-Heisenberg algebra. It is argued that the existence of an…

Quantum Physics · Physics 2009-09-29 João da Providência , Natália Bebiano , João Pinheiro da Providência

A Hamiltonian operator $\hat H$ is constructed with the property that if the eigenfunctions obey a suitable boundary condition, then the associated eigenvalues correspond to the nontrivial zeros of the Riemann zeta function. The classical…

Quantum Physics · Physics 2017-04-04 Carl M. Bender , Dorje C. Brody , Markus P. Müller