Problems of Condensed Matter Physics (Contemporary Fundamental Physics)

The present book includes eight works on some contemporary problems of condensed matter physics. The choice of the topics reflects the scientific interest of the editors. We hope the book will find a wide circle of readers. Chapter 1 examines critically the studies of the quasiregular (quasiperiodic) heterostructures. The minimal basis of mathematical background required for a more rigorous characterization of spectra of quasiregular sequences is summarized and then the self-similarity and the fractal nature of the spectrum are discussed on this basis. Chapter 2 presents some new aspects of the empirical tight-binding model and its applications for semiconductor heterostructure calculations. The objective is to show how best to exploit the power and circumvent the limitations of the method as applied to heterostructure calculations. An introduction to the phenomenology of type II superconductivity and sandpile physics is given in Chapter 3. Key experiments on vortex avalanches performed in the last five years are reviewed and some new experiments are suggested. Chapter 4 shows that the joint use of the surface Green function matching method and the full transfer matrix technique simplifies greatly the study of inhomogeneous media. As applications, the transverse elastic waves in finite Fibonacci superlattices are studied. Chapter 5 presents recent progress in understanding the physics of a novel class of one-dimensional ferrimagnetic Heisenberg systems composed of different antiferromagnetically coupled quantum spins in the elementary cell. Finite temperature properties of electron-phonon systems in semiconducting heterostructures are considered in Chapter 6. The long standing Boltzmann-Loschmidt polemic which confronts irreversible Thermodynamics with reversible Mechanics is revived in Chapter 7. The possibility offered by NMR to invert the direction of time (quantum Loschmidt daemon) in a many-body system is explored. The whole set of experiments indicates that there is quantum chaos intrinsic to the many-body spin dynamics in the thermodynamic limit. Chapter 8 describes a simple model based on the Thomas-Fermi-Dirac approximation for an inhomogeneous hole gas. This model gives results in good agreement with the experiment and self-consistent calculations for delta-doped quantum wells.