ФИЗИКА. Учебник и практикум для академического бакалавриата
The article is devoted to the problem of interpreting the concept of time in the context of some concepts of modern physics. This fundamental concept inevitably arises in physical theories, but there is still no adequate description of it in the philosophy of science. In the theory of relativity, quantum field theory, the standard model of elementary particle physics, the theory of loop quantum gravity, superstring theory, and other recent theories, the idea of time is explicitly or implicitly present. Sometimes, as, for example, in the special theory of relativity, it plays a pronounced role, sometimes not, but somehow it is and is implied by the content of the theory and in some cases by its mathematical apparatus. Especially important for solving the problem is the fundamental difference between the space-time processes of the microcosm and the macrocosm. In this connection, there is a need to understand time as it appears in modern physics, its description in the language of philosophy (there is also no satisfactory mathematical apparatus for describing time). This will make it possible to get closer to the answer to the question about the properties of time and, if not answered, then formulate the correct question about what it is. To this end, this study analyzes the key concepts of modern physics, taking into account the historical-scientific and historical-philosophical perspectives, which in some cases allows us to detect the continuity of ideas related to the understanding of time, their development, as well as the emergence of fundamentally new ones. In the course of the analysis, the characteristics of time that are correct from the point of view of physical theory are formulated, and an attempt is made to raise the question of the nature of time. Based on the work done, conclusions are drawn about the current state of the problem and the prospects for its solution.
The problem of time is not an entirely physical problem. Physics itself does not contain a "time theory". That is particularly true in the sense that physics has not made any direct attempts to find the natural-science definition of the notion of time. Nevertheless, the concept of time emerges in science one way or another and still requires an explanation. Time fulfills an important role in the physics of XX and XXI centuries, though often a hidden one. Such a statement could be applied to both theories of macrocosm and microcosm. In the theory of relativity, time has been established as a secondary feature, a derivative of velocity and mass. However, it exists (although, as an illusion) and yet evokes the need of its philosophical interpretation. In quantum field theory time also (though implicitly) occurs according to the interpretation of the experiment results - for example, “where the particle was before its observation”. Such “before”-cases indicate the very presence of time (more precisely, the observer`s perception of its presence). Further theories, which have been the attempts to solve the problem of incompatibility of general relativity theory and quantum mechanics, such as the theory of loop quantum gravity, superstring theory, Shape Dynamics and others, also mention the concept of time. Time fulfills there a definite role and again evokes the question of its explanation in the frameworks of these theories. Most importantly, to find an exact meaning of this “time” term used here. This article deals with the problem of time in the context of several theories of modern physics. In particular, it attempts to give a definition of the term of time in relation to the philosophy of physics (physics itself does not characterize it). Such a task formulation has its relevance and novelty due to the facts that the discourse on the nature of time is still stipulated by Zeno`s paradoxes, and the philosophy of science uses the obsolete vocabulary while describing the term. However, evidence suggests that modern physics has developed the new rules, or to be more precise, has stated the new principles, which the philosophy of science can not take into consideration without changing its vocabulary (the last also involves the modernization of intellectual intuition).
We consider the “Matthew effect” in the citation process which leads to reallocation (or misallocation) of the citations received by scientific papers within the same journals. The case when such reallocation correlates with a country where an author works is investigated. Russian papers in chemistry and physics published abroad were examined. We found that in both disciplines in about 60% of journals Russian papers are cited less than average ones. However, if we consider each discipline as a whole, citedness of a Russian paper in physics will be on the average level, while chemistry publications receive about 16% citations less than one may expect from the citedness of the journals where they appear. Moreover, Russian chemistry papers mostly become undercited in the leading journals of the field. Characteristics of a “Matthew index” indicator and its significance for scientometric studies are also discussed.
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
Radiation conditions are described for various space regions, radiation-induced effects in spacecraft materials and equipment components are considered and information on theoretical, computational, and experimental methods for studying radiation effects are presented. The peculiarities of radiation effects on nanostructures and some problems related to modeling and radiation testing of such structures are considered.
This volume presents new results in the study and optimization of information transmission models in telecommunication networks using different approaches, mainly based on theiries of queueing systems and queueing networks .
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.