Surface magnetism: phase transitions in quantum and classical models

2003 ◽  
Vol 319 ◽  
pp. 319-330 ◽  
Author(s):  
J. Cabral Neto ◽  
J.Ricardo de Sousa
2020 ◽  
Vol 3 ◽  
pp. 18-29
Author(s):  
Valery Nekhamkin ◽  

Introduction The article is focused on theoretical and methodological analysis of a number of social dynamics models that appeared on the basis of non-classical science. They are “challenge — response”, self-organization, a cycle of phase transitions “birth — life — death”, and “zone model”. The author reveals heuristic potential of each model, its strengths and weaknesses in the methodological aspect. The aim of the study is to consider the models of social dynamics that appeared on the basis of non-classical science in social cognition, identify their methodological foundations; compare these theoretical constructs with each other, and to improve these structures in theoretical and methodological aspects. Methods The following general scientific methods were used in the study: modeling, structural-functional, systemic and comparative analysis. The scientific novelty of the study. The author traces evolution of how the models under consideration have been forming in the framework of social cognition, and points out the epistemological foundations of their occurrence. In the “challenge-response” model, the author identifies its basic ideas and classifies the sources that generate historical “challenges” and the entities that form “answers” to them. The author specifies that the model of self-organization appeared long before the 20th century, but only thanks to the systematic approach and synergetics it acquires the necessary theoretical level. The author also points out positive aspects and limitations of the self-organization model in relation to social cognition. The author specifies the full structure of the “zone model” in social cognition, which includes the following elements: the center, the middle part, the intermediate space, and the periphery. Modifications of this model are shown in the framework of the world-system approach and other social theories. Results. The study demonstrates that in relation to each model, empirical material was first accumulated, and only then it was theoretically generalized on the basis of non-classical science. It is shown that the main merit of the world-system analysis is creating a “zone” model of social dynamics. The author recognizes that the zone model to the maximum extent includes other theoretical constructions: “challenge - answer”, self-organization, the cycle of phase transitions “birth - life - death”. It is assumed that in the future, theoretical approaches in the humanities are more likely to include new methodological tools. Conclusions. The author reveals continuity of intellectual instruments among various non-classical models of social dynamics, shows separate stages of the models evolution. It is stated that in the framework of the non-classical methodology of social cognition, there is a place for the approaches generated by classical science (for example, the assumption of linearity as a way of developing society).


2006 ◽  
Vol 13 (02) ◽  
pp. 113-117 ◽  
Author(s):  
Robert Alicki

Using few very general axioms which should be satisfied by any reasonable theory consistent with the Second Law of Thermodynamics we argue that: a) "no-cloning theorem" is meaningful for a very general theoretical scheme including both quantum and classical models, b) in order to describe self-replication, Wigner's "cloning" process should be replaced by a more general "broadcasting", c) "separation of species" is possible only in a non-homogeneous environment, d) "parent" and "offspring" must be strongly correlated. Motivated by the existing results on broadcasting which show that only classical information can self-replicate perfectly we discuss briefly a classical toy model with "quantum features" — overlapping pure states and "entangled states" for composite systems.


1992 ◽  
Vol 06 (14) ◽  
pp. 2531-2547 ◽  
Author(s):  
G. BARBERO ◽  
T. BEICA ◽  
R. MOLDOVAN ◽  
A. STEPANESCU

The influence of the surface on the phase transitions is discussed. Classical models are reviewed and critically analyzed. Starting with a multilayer model, a new form of the surface energy is proposed. Our model predicts, contrary to previous models, a surface order parameter different from zero in a temperature range above the critical temperature characterizing the bulk phase transition. The application of the model to the evaluation of the surface tension gives results in agreement with experimental data.


1980 ◽  
Vol 41 (C1) ◽  
pp. C1-39-C1-41
Author(s):  
A. J. Freeman ◽  
C. S. Wang ◽  
H. Krakauer ◽  
M. Posternak

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