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Fourier transforms quantization

The periodic-orbit quantization can be used to calculate not only the resonances but also the full shape of the photoabsorption cross section using (2.26) and (2.27). This semiclassical formula for the cross section separates in a natural way the smooth background from the oscillating structures due to the periodic orbits. In this way, the observation of emerging periodic orbits by the Fourier transform of the vibrational structures on top of the continuous absorption bands can be explained. [Pg.561]

An example of a typical sequence of onset times is shown in Figure 9.12a. Implied in the figure is that in general there can be more than one onset time per analysis frame. Although any one of the onset times can be used, in the face of computational errors due to discrete Fourier transform (DFT) quantization effects, it is best to choose the onset time which is nearest the center of the frame, since then the resulting phase errors will be minimized. This procedure determines a relative onset time, which is in contrast... [Pg.487]

If there is no explicit external electromagnetic field, the covariant field equations determine a self-interaction energy that can be interpreted as a dynamical electron mass Sm. Since this turns out to be infinite, renormalization is necessary in order to have a viable physical theory. Field quantization is required for quantitative QED. The classical field equation for the electromagnetic field can be solved explicitly using the Green function or Feynman propagator GPV, whose Fourier transform is —gllv/K2, where k = kp — kq is the 4-momentum transfer. The product of y0 and the field-dependent term in the Dirac Hamiltonian, Eq. (10.3), is... [Pg.184]

Systems in the collinear eZe configuration which have tori would be the antiproton-proton-antiproton (p-p-p) system, the positronium negative ion (Pr- e-e-e)), which corresponds to the case of Z= 1, = 1, and If these systems have bound states, we can see the effect of our finding in the Fourier transform of the density of states for the spectrum. For a positronium negative ion, the EBK quantization was done [34]. Stable antisymmetric orbits were obtained and were quantized to explain some part of the energy spectrum. As hyperbolic systems, H and He have been already analyzed in Refs. 11 and 17, respectively. Thus, Li+ is the next candidate. We might see the effect of the intermittency for this system in quantum defect as shown for helium [14]. [Pg.330]

This was the first indication of what [19] became the proposal to use inverse Fourier transforms for quantization, the now so-called Weyl quantization. We do not rely on this suggestion as Bom and Jordan had stated that Weyl s approach was too heavy for the introduction of quantum mechanics to physics. Having so stated, Bom and Jordan made their own approach. Thus, it became more incomprehensive to the chemists. [Pg.84]

There is a definite possibility of using classical physical quantities under operator companions, that is, an approach to quantization [ 19]. If a classical quantity was expressed by a function// , q) of the canonical variables, p, q, the Fourier transform of/can be used. Then,/is back-transformed from by... [Pg.84]

The quantization of the classical observables, p for P and q for Q, and the non-commutative P and Q led to a fundamental difficulty for an observable given as a function ft p, q) of the basic dynamical variables p and q. Weyl s unitary representation approach avoided this difficulty. The inverse operator of the Fourier transform (3.20) gave a unique well-determined assignment,/for F, of the Hermitian operators to the real-valued quantities. The same proposition can be advanced for electric variables such as the amount of electric charge, a as the classical observable, which after the quantization leads to Moreover, dynamical variables that are expressly related to the current intensity i as the classical observable yield after quantization to I. The same has to occur to the magnitude of the electric potential from v to V, after quantization of the classical observable. [Pg.85]

Elementary excitations also include single particle diffusive excitations beside quantized vibrations (i.e., molecular vibrations and vibrations of the crystal as a whole associated with phonons/magnons). Consider the incoherent dynamic structure factor 5snc(Q,(o), which is the Fourier transform pair of the time-dependent self-correlation function, compare... [Pg.1538]

Many DSP concepts can be demonstrated by examples which involve a great deal of computation. A list of some of the concepts is as follows convolution, filtering, quantization effects, etc. The curriculum begins with discrete Fourier transform (DFT). DFT is derived from discrete-time Fourier transform expression. The continuous and discrete Fourier transform are covered in Signals and Systans. The flow of the topics is as follows DFT, properties of DFT, Fast Fourier Transform, Infinite Impulse Response filter and Finite Impulse Response fillers and filter structures. If the topics are linked to a project with each block of the project demonstrating the various topics of the curriculum, it is easier for the student to comprehend what is being taught. [Pg.74]

Usefulness of any proposed scheme is that it reduces the PAPR and is not computationally complex. In our work we modified an existing promising reduction technique, SLM by using Learning Vector Quantization (LVQ) network. In a SLM system, an OFDM symbol is mapped to a set of quasi-independent equivalent symbols and then the lowest-PAPR symbol is selected for transmission. The tradeoff for PAPR reduction in SLM is computational complexity as each mapping requires an additional Inverse Fast Fourier transform (IFFT) operation in the transmitter. By the Learning Vector Quantization based SLM (LVQ-SLM), we eliminate the additional IFFT operations, getting a very efficient PAPR reduction technique with reduced computational complexity. [Pg.107]

FFT = fast Fourier transform GWP = Gaussian wave-packet MCTDSCF = multiconfiguration TDSCF SQ = second quantization TDGSCF = time-dependent group SCF TDSCF = time-dependent SCF TDSE = time-dependent Schrddinger equation. [Pg.1588]

We then come from spin operators to second quantization operators in a standard manner, expand the square root in Eq. (2.3) in a bilinear operator form, and, finally, perform the Fourier transform. As a result, we obtain the following expression for the spin wave energy ... [Pg.402]


See other pages where Fourier transforms quantization is mentioned: [Pg.133]    [Pg.508]    [Pg.634]    [Pg.57]    [Pg.66]    [Pg.194]    [Pg.201]    [Pg.9]    [Pg.142]    [Pg.96]    [Pg.303]    [Pg.35]    [Pg.632]    [Pg.412]   
See also in sourсe #XX -- [ Pg.242 ]




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Quantization

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