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Frohlich waves

Nonlinear dynamical effects on one-dimensional systems such as biomolecular chains, e.g., Davydov solitons, can also be analyzed in terms of boson condensation. " In the Frohlich wave case, the condensation... [Pg.265]

H. Schnitzler, U. Frohlich, T.K.W. Boley, A.E.M. Clemen, J. Mlynek, A. Peters, and S. Schiller, All-solid-state tunable continuous-wave ultraviolet source with high purity and frequency stability. Applied Optics 41(33), 7000-7005 (2002). [Pg.224]

Frohlich and Pelzer (1955) determined the frequencies of longitudinal waves in matter described by the three simple dielectric functions—Lorentz, Drude, and Debye—discussed in this chapter. [Pg.267]

Rohrbeck, W., Chilla, E., Frohlich, H.-J., and Riedel, J. (1991). Detection of surface acoustic waves by scanning tunneling microscopy. Appl. Phys. A 52, 344—7. [292]... [Pg.340]

Optical study indicates that at low temperatures the low-energy electronic properties of some organic metal-like conductors (e.g., TTF-TCNQ) are dominated by charge density wave (CDW) effects. Frequency-dependent conductivity of TTF-TCNQ, obtained from the IR reflectance, at 25 K displays a double-peak structure with a low-frequency band near 35 cm-1 and a very intense band near 300 cm-1 [45]. The intense band may be ascribed to single-particle transitions across the gap in a 2kF (Peierls) semiconducting state, while the 35-cm-1 band is assigned to the Frohlich (i.e., CDW) pinned mode. Low-temperature results based on the bolometric technique [72,73] (Fig. 15) confirm the IR reflectance data. Such a con-... [Pg.255]

Impurity Pinning of Charge Density Wave in the Peierls-Frohlich State 217... [Pg.9]

IMPURITY PINNING OF CHARGE DENSITY WAVE IN THE PEIERLS-FROHLICH STATE... [Pg.217]

The dynamics of impurity pinning of the charge density wave and the frequency dependence of conductivity are investigated in the one-dimensional Peierls-Frohlich state. [Pg.217]

Low-dimensional metals have certainly led to one of the more interesting and fruitful chapters in modern soUd state science. The interest on these materials dates back to the theoretical work of Peierls [192] and Frohlich [193] more than 40 years ago. However it was the seminal work by Wilson et al. [194] on transition metal dichalcogenides, as well as the practically simultaneous discovery of the first truly organic molecular metal, TTF-TCNQ (TTF tetrathiafulvalene, TCNQ tetracyanoquinodimethane) [195, 196] which launched a great effort on their study. Many of the interesting properties of these materials are related to the special topology of their Fermi surface (FS) [194, 197]. When a piece of the FS can be translated by a vector q and superimposed on another piece of the FS, this FS is said to be nested by the vector q. Metals with a nested FS are susceptible to a modulation with wave vector q of their charge or spin density, which destroys the nested part of the FS. [Pg.150]

The BCS and Little models for superconductivity are both based on the formation of pairs of electrons with an effective attractive interaction due to phonons or excitons respectively. Recently, J. Bardeen (8,28) revived a model, originally presented by Frohlich in 1954 (152), as a possible explanation of the reported anomalous conductivity behavior of (TTF)(TCNQ) (97). This model predates the BCS theory and relies on the direct interaction between electrons and the one-dimensional lattice resulting in the formation of charge density waves. The model has also been applied to the one-dimensional metal K2Pt(CN)4Bro.3o(H20)s (72, 457). [Pg.31]

A very important feature of the Frohlich model is that the lattice distortion and the charge density wave need not be fixed to the frame of reference of the lattice (i.e., the phase of the distortion need not be fixed). The electrons which make up the charge density wave may then move as a unit (collective charge transport) with a large effective charge and large effective mass leading to enhanced conductivity. [Pg.32]

Fig. 33. Far infrared to uv reflectivity of K2Pt(CN)4Bro.3o(H20)8 for light polarized parallel to the conducting axis. The dashed line is for the sample at 300°K, the solid line 40 K. The low frequency structure (50cm i) at 40 °K is assigned to the response of a pinned charge density wave (pinned Frohlich mode) (72). Fig. 33. Far infrared to uv reflectivity of K2Pt(CN)4Bro.3o(H20)8 for light polarized parallel to the conducting axis. The dashed line is for the sample at 300°K, the solid line 40 K. The low frequency structure (50cm i) at 40 °K is assigned to the response of a pinned charge density wave (pinned Frohlich mode) (72).
ABSTRACT We present a dynamical scheme for biological systems. We use methods and techniques of quantum field theory since our analysis is at a microscopic molecular level. Davydov solitons on biomolecular chains and coherent electric dipole waves are described as collective dynamical modes. Electric polarization waves predicted by Frohlich are identified with the Goldstone massless modes of the theory with spontaneous breakdown of the dipole-rotational symmetry. Self-organization, dissipativity, and stability of biological systems appear as observable manifestations of the microscopic quantum dynamics. [Pg.263]

H. Frohlich has introduced, in a framework of far-from-equilibrium processes, coherent electric polarization waves as the physical agent able to control the working of distant and separate parts of the system, making them cooperative. On the other hand, it has been shown that biomolecules are able to host on their own chains, in a conservative framework, highly nonlinear subdynamics which give rise to deep structural and conformational changes. [Pg.264]

We are going to explore the consequences of the dynamical rearrangement of the symmetry in the two cases of the Davydov vibrational solitons on macromolecules and of the Frohlich electric waves in the whole biological system. In the first case we deal with an explicit form of the equations, so that a complete treatment is possible, while in the second case we limit ourselves to the consideration of the dynamical rearrangement of the symmetry and of the consequent appearance of massless modes. [Pg.270]

Up to now, different kinds of evidence can be quoted, which support the Frohlich proposal of electric waves in living matter. First of all, we mention those resonance experiments where external electromagnetic waves of selected frequencies interact with biological targets inducing macroscopic nonthermal consequences. There is a growing literature about microwave interaction with different types of cells. It has been observed that at given frequencies the effects occur only when a threshold is overcome and are independent from different intensities of irradiation. [Pg.283]

F. Kaiser, Coherent Oscillations in Biological Systems. II. Limit Cycle Collapse and the Onset of Travelling Waves in Frohlich s Brain Wave Model, Z. Naturforsch. 33a, 418-431 (1978). [Pg.311]

Sphere. A complete description of the coupling of an electromagnetic wave and the eigenmodes of an isolated sphere of any size, given by polariton theory based on Mie s formalism (Section 1.10), indicates that all modes of a sphere-shaped crystal are radiative [293, 298], These modes are called surface modes since their origin lies in the finite size of the sample [297]. For very small spheres, there is only the lowest order surface mode (the Frohlich mode), which is neither transverse nor longitudinal [293]. Its frequency (the Frohlich frequency) is given by... [Pg.220]

Systematic location errors could occur due to high deformation of the rock specimen. To minimize the travel-time residuals, systematic location errors associated with picking errors and the velocity variations due to microcracking were removed by the application of the joint-hypocenter determination (JHD) method (Frohlich 1979). Using the JHD method, "station corrections" can be determined that account for consistent inaccuracies of the wave velocity along the travel path especially near sensor positions. To delineate structures inside a clouded AE event distribution the collapsing method, which was first reported by Jones and Steward [1997], can be applied. This method describes how the location of an AE event can be moved within its error ellipsoid in order that the distribution of movements for every event of a cloud approximates that of normally distributed location uncertainties. This does not make the location uncertainties in the dataset smaller but it highlights structures already inherent within the unfocussed dataset. [Pg.289]

Schnitzler H, Frohlich U, Boley TKW, Clemen AEM, Mlynek J, Peters A, Schiller S. 2002. All-solid-state tuneable continuous-wave ultraviolet source with high spectral purity and fre quency stability . Appl. Opt. 41(33) 7000-7005. [Pg.471]

Frohlich (1954) proposed the possibihty of superconductivity in 1-D metals due to spontaneously sliding charge density waves (CDWs). [Pg.321]


See other pages where Frohlich waves is mentioned: [Pg.266]    [Pg.285]    [Pg.266]    [Pg.285]    [Pg.69]    [Pg.77]    [Pg.185]    [Pg.3421]    [Pg.1]    [Pg.27]    [Pg.314]    [Pg.578]    [Pg.20]    [Pg.32]    [Pg.49]    [Pg.65]    [Pg.180]    [Pg.265]    [Pg.266]    [Pg.279]    [Pg.297]    [Pg.52]    [Pg.6]    [Pg.527]    [Pg.199]   
See also in sourсe #XX -- [ Pg.266 ]




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