دانلود کتاب فیزیک آماری و ماده چگال

The subject of statistical physics is to study the physical properties and behavior of various macroscopic systems and condensed media under the thermodynamic (heat) equilibrium. The thermodynamic or heat equilibrium implies that the physical system can wholly be described by the canonical Gibbs distribution. The main difficulty that arises here is to calculate the partition function and corresponding thermodynamic potential. At present, statistical physics is the basis of condensed matter physics and the tool for studying a variety of condensed media. The condensed medium or macroscopic system is usually understood as a physical system consisting of the macroscopic number of particles and having the macroscopic number of degrees of freedom. In essence, the term, macroscopic, implies implicitly the limiting transition to the infinite system having, for example, an infinite number of particles or volume. At the same time, the physical system in itself can also represent a single particle but interacting with the macroscopic thermal bath. As a typical example of condensed media, we can mention gases, normal and superfluid liquids, crystalline and amorphous solids, superconductors, and various magnets. The starting point in the study of condensed matter is the introduction and determination of the necessary thermodynamic quantities depending on the type of the physical system to be explored. For example, this may be temperature, volume, pressure, polarization, magnetization, and thermodynamic potentials as functions of these quantities, e.g. energy, free energy, and entropy. The statistical physics is one of three main courses of theoretical physics which students of Moscow Institute of Physics and Technology study. Over the past 50 years, statistical physics and condensed matter physics have developed rapidly in the scientific context and have achieved outstanding success due, in particular, to the development and usage of specific models and mathematical methods. The latter often turns out to be very complicated, requires cumbersome calculations, and may simply be inaccessible without special mathematical training. However, these successes of statistical physics and condensed matter physics have not yet found an accessible and complete reflection in the textbooks proposed for the students of physical specialties. Apparently, this may be associated with the following reasons. Firstly, it is necessary to convey the material to students, using the simplest mathematical apparatus. Secondly, it is the limited time frame that is assigned to studying the subject. Currently,MoscowInstitute of Physics and Technology, in contrast to the annual course of quantum mechanics, has a single semester for studying the statistical physics course. This is obviously insufficient due to the extent of the subject of statistical and condensed matter physics. Thus, it is necessary to enhance the requirements for selecting the instructional content that students of physical universities should study under single semester course. The practice of teaching the statistical physics course has led me to the following. The content that relates to the principles, basic statements of statistical physics, and properties of classical and quantum ideal gases poses no difficulties for the MIPT students. The learning problems will concern a noticeable amount of students when they start to study the physical properties of non-ideal quantum systems and condensed media since this requires a comprehension of more complicated physical models and application of more sophisticated mathematical tools. The purpose of the present textbook is to help the students, future physicists, to master the basic elements of statistical physics and learn how to apply its methods in practice. For understanding the content of the book, it is sufficient to be familiar with the basic concepts of statistical physics in the body of conventional general physics courses. When writing the book, the author came across some difficulties associated with the reasonable text volume and, therefore, with the necessity to select the actual content from the numerous number of interesting physical phenomena in condensed media. Here the author’s personal preferences and work experience in this field of physics are displayed as well as his viewpoint of statistical physics as a necessary part of the full course of theoretical physics. The structure of the book proposed to the reader is easy to understand from its contents. In a few words, the author can say that the book is devoted both to the fundamental laws of statistical physics and to most interesting physical phenomena occurring in condensed media. The book begins with explaining the basic principles of statistical physics based on the canonical Gibbs distribution and their connection with the laws of classical thermodynamics. Next, the thermodynamic properties are considered of non-interacting media representing classical (Boltzmann) ideal gases and quantum Fermi and Bose ideal gases. This section concludes with the thermal properties of black radiation and solid crystals. The next section is devoted to the thermodynamic fluctuations, various phase transitions in the mean-field approximation, and basics of critical phenomena with the approximate calculation of critical indices.