### Abstract

We present an intuitive and scalable algorithm for the diagonalization of complex symmetric matrices, which arise from the projection of pseudo-Hermitian and complex scaled Hamiltonians onto a suitable basis set of “trial” states. The algorithm diagonalizes complex and symmetric (non-Hermitian) matrices and is easily implemented in modern computer languages. It is based on generalized Householder transformations and relies on iterative similarity transformations T → T′ = Q^{T}T Q, where Q is a complex and orthogonal, but not unitary, matrix, i.e.Q^{T} = Q^{−1} but Q^{+} ≠ Q^{−1}. We present numerical reference data to support the scalability of the algorithm. We construct the generalized Householder transformations from the notion that the conserved scalar product of eigenstates Ψ_{n} and Ψ_{m} of a pseudo-Hermitian quantum mechanical Hamiltonian can be reformulated in terms of the generalized indefinite inner product ∫ dxΨ_{n}(x, t) Ψ_{m}(x, t), where the integrand is locally defined, and complex conjugation is avoided. A few example calculations are described which illustrate the physical origin of the ideas used in the construction of the algorithm.

Original language | English |
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Article number | 93 |

Journal | European Physical Journal Plus |

Volume | 128 |

Issue number | 8 |

DOIs | |

Publication status | Published - Aug 1 2013 |

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### ASJC Scopus subject areas

- Physics and Astronomy(all)

### Cite this

*European Physical Journal Plus*,

*128*(8), [93]. https://doi.org/10.1140/epjp/i2013-13093-1

**Generalized Householder transformations for the complex symmetric eigenvalue problem.** / Noble, J. H.; Lubasch, M.; Jentschura, U.

Research output: Contribution to journal › Article

*European Physical Journal Plus*, vol. 128, no. 8, 93. https://doi.org/10.1140/epjp/i2013-13093-1

}

TY - JOUR

T1 - Generalized Householder transformations for the complex symmetric eigenvalue problem

AU - Noble, J. H.

AU - Lubasch, M.

AU - Jentschura, U.

PY - 2013/8/1

Y1 - 2013/8/1

N2 - We present an intuitive and scalable algorithm for the diagonalization of complex symmetric matrices, which arise from the projection of pseudo-Hermitian and complex scaled Hamiltonians onto a suitable basis set of “trial” states. The algorithm diagonalizes complex and symmetric (non-Hermitian) matrices and is easily implemented in modern computer languages. It is based on generalized Householder transformations and relies on iterative similarity transformations T → T′ = QTT Q, where Q is a complex and orthogonal, but not unitary, matrix, i.e.QT = Q−1 but Q+ ≠ Q−1. We present numerical reference data to support the scalability of the algorithm. We construct the generalized Householder transformations from the notion that the conserved scalar product of eigenstates Ψn and Ψm of a pseudo-Hermitian quantum mechanical Hamiltonian can be reformulated in terms of the generalized indefinite inner product ∫ dxΨn(x, t) Ψm(x, t), where the integrand is locally defined, and complex conjugation is avoided. A few example calculations are described which illustrate the physical origin of the ideas used in the construction of the algorithm.

AB - We present an intuitive and scalable algorithm for the diagonalization of complex symmetric matrices, which arise from the projection of pseudo-Hermitian and complex scaled Hamiltonians onto a suitable basis set of “trial” states. The algorithm diagonalizes complex and symmetric (non-Hermitian) matrices and is easily implemented in modern computer languages. It is based on generalized Householder transformations and relies on iterative similarity transformations T → T′ = QTT Q, where Q is a complex and orthogonal, but not unitary, matrix, i.e.QT = Q−1 but Q+ ≠ Q−1. We present numerical reference data to support the scalability of the algorithm. We construct the generalized Householder transformations from the notion that the conserved scalar product of eigenstates Ψn and Ψm of a pseudo-Hermitian quantum mechanical Hamiltonian can be reformulated in terms of the generalized indefinite inner product ∫ dxΨn(x, t) Ψm(x, t), where the integrand is locally defined, and complex conjugation is avoided. A few example calculations are described which illustrate the physical origin of the ideas used in the construction of the algorithm.

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U2 - 10.1140/epjp/i2013-13093-1

DO - 10.1140/epjp/i2013-13093-1

M3 - Article

VL - 128

JO - European Physical Journal Plus

JF - European Physical Journal Plus

SN - 2190-5444

IS - 8

M1 - 93

ER -