Physics foundational theories

The new theory developed from two independent publications - a purely mathematical model and the Schrodinger alternative with a clear physical foundation. The latter was immediately branded as a futile attempt to revive the concepts of classical physics, already refuted by the new paradigm. 

It is appropriate here to make some remarks on the physical foundations of thermal conductivity. The dependence of thermal conductivity on temperature has been experimentally recognized. However, there is no universal theory explaining this dependence. Gases, liquids, conducting and insulating solids can each be explained with somewhat different microscopic considerations. Although the text is on the continuum aspects of heat transfer, the following remarks are made for some appreciation of the microscopic aspects of thermal conductivity. 

Before dealing with the mathematical theory of atomic mechanics we shall give a brief account of its physical foundations. There are two sources to be considered on the one hand the theory of thermal radiation, which led to the discovery of the quantum laws on the other, investigations of the structure of atoms and molecules. 

Our foundational theories in physics are generally credited as being the very best science that we have got. Their universality of scope, their exactness of prediction, their depth of explanatory force are all unmatched by the theoretical accomplishments of the various special sciences. But careful reflection on just how these theories function to provide us with descriptions, predictions, and explanations appropriate to the world in which we live shows us that there are profound puzzles lurking in the way these theories function in our scientific account of the world, puzzles that beg for the detailed, careful, and thorough exploration of the methodologist of science. 

Even within physics itself, many have convincingly argued, there are many systems of the world whose behavior can be dealt with only by the use of concepts and regularities that fall outside the scope of the foundational theories. In describing and explaining the behavior of these systems, aspects of the foundational theories may sometimes be invoked, but one can deal with these systems fully only if one introduces novel concepts, and novel regularities framed in these novel terms, that go beyond the foundational theories and that themselves may have limited domains of applicability. 

I have asserted that important methodological observations have sometimes led to extreme conclusions. Thus the observation that the applicability of our foundational physics to really predict and explain the behavior of actual systems is confined to a very limited set of such systems in the world has led, falsely, I think, to the conclusion that these theories are not applicable in any sense to the whole world and to versions of ontological pluralism. Again, the observation that the application of our foundational theories to real systems generally rests upon the need to idealize these systems in order that they can be dealt with by the foundational theories might lead, once more falsely, I think, to such claim as that the foundational theories are meant to apply only to abstract models and not to the real systems themselves. 

The physical property values of materials provide empirical data for the verification and refinement of theory. The greater the purity of a material, the more precisely its corresponding characteristic properties will refine foundational theory. For many materials, particularly elemental materials, zone refinement provides an entirely new avenue of study and research, one that focuses on the innate nature of the material. 

The combined influence of physical-chemical and mechanical factors on the processes of deformation and fracture is the subject of physical-chemical mechanics, which constitutes the foundation of the physical-chemical theory of the strength of solids. One can identify two distinctive areas of engineering that are closely associated with these processes ... 

Chen Y, Lee J D and Eskandarian A (2003) Examining the physical foundation of continuum theories from the viewpoint of phonon disperaon relation, Int J Eng Sci 41 61-83. 

Likewise it is sometimes said that the physics of condensed matter provides the fundamental physical foundations for a theory of chemistry. However the precise chemical nature of materials is usually of little interest in general quantmn theories of some physical property which is exhibited in different materials. A quantmn description of the physical properties of bulk matter — diffraction experiments, electrical conductivity, ferroelectricity, magnetism, optical properties, superconductivity etc. — does not involve the classical picture of matter based on atoms and molecules (it is based on interacting electron and nuclear fields [Anderson,... 

D. O. Shah and W. C. Hsieh, Microemulsions, Liquid Crystals and Enhanced Oil Recovery, in Theory, Practice, and Process Principles for Physical Separations, Engineering Foundation, New York, 1977. 

The purpose of this chapter is to provide an introduction to tlie basic framework of quantum mechanics, with an emphasis on aspects that are most relevant for the study of atoms and molecules. After siumnarizing the basic principles of the subject that represent required knowledge for all students of physical chemistry, the independent-particle approximation so important in molecular quantum mechanics is introduced. A significant effort is made to describe this approach in detail and to coimnunicate how it is used as a foundation for qualitative understanding and as a basis for more accurate treatments. Following this, the basic teclmiques used in accurate calculations that go beyond the independent-particle picture (variational method and perturbation theory) are described, with some attention given to how they are actually used in practical calculations. 

Linear response theory is an example of a microscopic approach to the foundations of non-equilibrium thennodynamics. It requires knowledge of tire Hamiltonian for the underlying microscopic description. In principle, it produces explicit fomuilae for the relaxation parameters that make up the Onsager coefficients. In reality, these expressions are extremely difficult to evaluate and approximation methods are necessary. Nevertheless, they provide a deeper insight into the physics. 

The development of the structural theory of the atom was the result of advances made by physics. In the 1920s, the physical chemist Langmuir (Nobel Prize in chemistry 1932) wrote, The problem of the structure of atoms has been attacked mainly by physicists who have given little consideration to the chemical properties which must be explained by a theory of atomic structure. The vast store of knowledge of chemical properties and relationship, such as summarized by the Periodic Table, should serve as a better foundation for a theory of atomic structure than the relativity meager experimental data along purely physical lines. ... 

During the nineteenth century the growth of thermodynamics and the development of the kinetic theory marked the beginning of an era in which the physical sciences were given a quantitative foundation. In the laboratory, extensive researches were carried out to determine the effects of pressure and temperature on the rates of chemical reactions and to measure the physical properties of matter. Work on the critical properties of carbon dioxide and on the continuity of state by van der Waals provided the stimulus for accurate measurements on the compressibiUty of gases and Hquids at what, in 1885, was a surprisingly high pressure of 300 MPa (- 3,000 atmor 43,500 psi). This pressure was not exceeded until about 1912. 

Following a brief section on Units and Dimensions (Section 4.2), Sections 4.3 and 4.4 review some of the key physical and chemical properties, respectively. Three important conservation laws are presented in Section 4.5. Basic engineering principles are discussed in Section 4.6, to present a foundation for the theory underlying the proper design and operation of a chemical process. 

The work on gas theory had many extensions. In 1865 Johann Josef Loschmidt used estimates of the mean free path to make the first generally accepted estimate of atomic diameters. In later papers Maxwell, Ludwig Boltzmann, and Josiah Willard Gibbs extended the rrratherrratics beyorrd gas theory to a new gerreralized science of statistical mechanics. Whenjoined to quantum mechanics, this became the foundation of much of modern theoretical con-derrsed matter physics. 

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