منابع مشابه
Anharmonic Frequency Analysis
A new numerical method of frequency analysis is described, designed mainly to search for discrete frequencies in a time series. An integral transform is applied twice to the data for different reference times. A complex amplitude within a selected narrow frequency band is obtained for each transform. The frequency is then determined from the phase change of the complex amplitude over the differ...
متن کاملAnharmonic Analysis of Lattice Field Theories
In a previous paper we showed that a class of real space renormalization group calculations could be reinterpreted as an orthogonal transformation of coordinates followed by an approximate (variational) evaluation of the resulting hamiltonian. Here we shall discuss the orthogonal transform method and concentrate on analytic rather than numerical results. The transform method may ultimately be m...
متن کاملPerturbative analysis of anharmonic chains of oscillators out of equilibrium
We compute the first-order correction to the correlation functions of the stationary state of a stochastically forced harmonic chain out of equilibrium when a small on-site anharmonic potential is added. This is achieved by deriving a suitable formula for the covariance matrix of the invariant state. We find that the first-order correction of the heat current does not depend on the size of the ...
متن کاملMultiple-Scale Analysis of the Quantum Anharmonic Oscillator.
Conventional weak-coupling perturbation theory suffers from problems that arise from resonant coupling of successive orders in the perturbation series. Multiple-scale perturbation theory avoids such problems by implicitly performing an infinite reordering and resummation of the conventional perturbation series. Multiple-scale analysis provides a good description of the classical anharmonic osci...
متن کاملDispersion corrected DFT approaches for anharmonic vibrational frequency calculations: nucleobases and their dimers.
Computational spectroscopy techniques have become in the last few years an effective means to analyze and assign infrared (IR) spectra of molecular systems of increasing dimensions and in different environments. However, transition from compilation of harmonic data to fully anharmonic simulations of spectra is still underway. The most promising results for large systems have been obtained, in o...
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ژورنال
عنوان ژورنال: Mathematics of Computation
سال: 1972
ISSN: 0025-5718
DOI: 10.2307/2005170