Background Dynamics Research Articles

The Lattice Dynamical Background of Classical Crystal Optics

physica status solidi (b)Volume 100, Issue 1 p. 9-41 Review Article The Lattice Dynamical Background of Classical Crystal Optics R. Claus, R. Claus Sektion Physik der Universität München Search for more papers by this author R. Claus, R. Claus Sektion Physik der Universität München Search for more papers by this author First published: 1 July 1980 https://doi.org/10.1002/pssb.2221000102Citations: 28 Schellingstr. 4, D-8000 München 40, BRD. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume100, Issue11 July 1980Pages 9-41 RelatedInformation

Some Further Comments on the Lattice Dynamical Background of Optical Activity in Crystals

physica status solidi (b)Volume 99, Issue 2 p. K83-K85 Short Note Some Further Comments on the Lattice Dynamical Background of Optical Activity in Crystals R. Claus, R. Claus Sektion Physik der Universität München Search for more papers by this author R. Claus, R. Claus Sektion Physik der Universität München Search for more papers by this author First published: 1 June 1980 https://doi.org/10.1002/pssb.2220990241Citations: 2 1) Schellingstr. 4, D-8000 München 40, BRD. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume99, Issue21 June 1980Pages K83-K85 RelatedInformation

On the lattice dynamical background of optical activity in crystals

AbstractThe lattice dynamical theory of crystal optical activity developed by Born is discussed in the view of polariton dispersion. Three major difficulties occur: 1) For large wave vectors k no continuous connection with the phonon dispersion branches as recorded by neutron scattering is found. 2) There are spectral regions in which two left‐ or two right‐circularly polarized waves with different k are expected. 3) Polariton group velocities in the Γ‐point remain undefined when time reversal is required. An alternative model omitting these difficulties is proposed. It is based on the assumption of the existence of anharmonic resonance coupling between orthogonally polarized polariton waves with degenerate dispersion branches.

A review of electronics design for auger electron spectroscopy

The technique of modulation phase-sensitive detection for Auger electron spectroscopy has changed little in principle since its inception in the late 1960's. However the 1970's have seen significant improvements with the introduction of highly-tuned preamplifiers, high performance oscillators, the use of integral rather than derivative spectra, and dynamical background substraction. These Improvements have largely been brought about by the availability of inexpensive integrated circuits (IC's) and by computer control. The authors have considered new modulation coupling approaches and the up-dating of high voltage ramp windowing circuits.

Poincaré- and gauge-invariant two-dimensional quantum chromodynamics

We present a canonical formulation of two-dimensional quantum chromodynamics in the axial or Coulomb gauge ${A}_{1}^{a}=0$. For consistency with the Lagrange equations of motion, the Hamiltonian must include a nontrivial dynamical background electric field term. This breaks translation invariance in the gauge-noninvariant sector. We argue, however, that for the purpose of calculating gauge-invariant physical quantities one can consider the naive theory defined by the Feynman rules without the background electric field. We show that the naive theory has an anomalous Poincar\'e algebra due to its non-Abelian character; the theory is Lorentz invariant only in the color-singlet sector. Because of this fact the quark propagator has a noncovariant pole, and the $i\ensuremath{\epsilon}$ prescription is different from the naive one. In the $N\ensuremath{\rightarrow}\ensuremath{\infty}$ limit (where $N$ is the number of colors) we can set up a two-component Bethe-Salpeter equation in the color-singlet sector to determine the spectrum of the theory. The resulting equation has an obvious interpretation in terms of forward- and backward-moving strings, and leads to the same spectrum of bound states as that obtained by 't Hooft in the light-cone gauge.