Le pluralisme politique à l’épreuve de la vie privée : entre normes et pratiques

L’espace des relations interpersonnelles et privées, en tant qu’espace de politisation et d’expression des choix politiques, est peu connu. C’est à une meilleure connaissance du « citoyen privé » et de la « politisation intime » que cet article veut contribuer, en étudiant les ressemblances et les divergences idéologiques au sein du cercle des proches. Présentant les résultats d’une enquête quantitative et représentative de la population française inédite, « Famille, amour et politique », réalisée par le CEVIPOF, il examine la filiation, la conjugalité, et l’amitié et montre les interactions et les transactions qui opèrent entre le système des normes et le système des affects des individus. La famille apparaît plus hétérogame politiquement tandis que le couple et le cercle des amis sont plus homogames. Toutefois, c’est le niveau de politisation des individus qui est en dernière instance le plus déterminant. Une affiliation politique affirmée, et tout particulièrement à gauche, ainsi qu’un intérêt marqué pour la politique, renforcent toujours l’homogamie politique au sein du cercle des proches, dans les principes comme dans les faits. Plus largement, l’article ouvre une réflexion sur l’espace de la vie privée en tant que terrain d’expérience des conditions de la pluralité démocratique.Little is known of the role played by private interpersonal relationships in politicization and the expression of political choices. This article aims to improve our understanding of “private citizens” and “personal politicization” through a study of ideological similarities and divergences within family and friendship circles. The analysis, based on findings from an unprecedented quantitative representative French population survey by the CEVIPOF (Center for the study of French political life) entitled “Famille, amour et politique” [Family, love and politics], examines filiation, conjugality and friendship, showing the interactions and transactions that take place between the system of norms and the system of individual feelings. Families appear more heterogamous politically, while couples and friendship circles are more homogamous. However, individuals’ level of politicization is ultimately the most determinant factor. Having a strong political affiliation, particularly on the left of the political spectrum, and a strong interest in politics always strengthens intra-circle political homogamy in terms of both principles and actions. At a more general level, the article reflects on the sphere of private life as a field for the development of conditions of democratic pluralism

Universal amplitude ratios from numerical studies of the three-dimensional O(2) model

We investigate the three-dimensional O(2) model near the critical point by Monte Carlo simulations and calculate the major universal amplitude ratios of the model. The ratio U_0=A+/A- is determined directly from the specific heat data at zero magnetic field. The data do not, however, allow to extract an accurate estimate for alpha. Instead, we establish a strong correlation of U_0 with the value of alpha used in the fit. This numerical alpha-dependence is given by A+/A- = 1 -4.20(5) alpha + O(alpha^2). For the special alpha-values used in other calculations we find full agreement with the corresponding ratio values, e. g. that of the shuttle experiment with liquid helium. On the critical isochore we obtain the ratio xi+/xi-_T=0.293(9), and on the critical line the ratio xi_T^c/xi_L^c=1.957(10) for the amplitudes of the transverse and longitudinal correlation lengths. These two ratios are independent of the used alpha or nu-values.Comment: 34 pages, 19 Ps-figures, Latex2e, revised version, to be published in J. Phys.

The heat capacity of nitrogen chains in grooves of single-walled carbon nanotube bundles

The heat capacity of bundles of closed-cap single-walled carbon nanotubes (SWNT) with one-dimensional chains of nitrogen molecules adsorbed in the grooves has been first experimentally studied at temperatures from 2K to 40K using an adiabatic calorimeter. The contribution of nitrogen C(T) to the total heat capacity has been separated. In the region 2-8K the behaviour of the curve C(T) is qualitatively similar to the theoretical prediction of the phonon heat capacity of 1D chains of krypton (Kr) atoms localized in the grooves of SWNT bundles. Below 3K the dependence C(T) is linear. Above 8K the dependence C(T) becomes steeper in comparison with the case of Kr atoms. This behaviour of the heat capacity C(T) is due to the contribution of the rotational degrees of freedom of the nitrogen molecules.Comment: 15 pages, 4 figure

Phonon spectrum and vibrational characteristics of linear nanostructures in solid matrices

The atomic dynamics of linear chains embedded in a crystalline matrix or adsorbed on its surface is studied. A linear chain formed by substitutional impurities in a surface layer and at the same time offsetting from this layer was analyzed particularly. This system models the actively studied experimentally structures in which gas molecules are adsorbed on the walls of the bundles of carbon nanotubes located in certain medium. It is shown that the quasi-1D features are typical for the chains in which the interatomic interaction is higher than the interaction between the atoms of the chain and the atoms of the crystal matrix. On the local phonon density of atoms of the chain, the transition to quasi-one-dimensional behavior has the form of the kink. In other words, it is the first (lowest-frequency) van Hove singularity, which in 3D structures (the system under consideration is generally three-dimensional) corresponds to the transition from closed to open constant-frequency (quasi-plane) surfaces. The local phonon densities of atoms in the chain have one-dimensional character at frequencies higher than the frequency of the van Hove singularity. The rms-amplitude of embedded chains atoms vibrations is calculated and the behavior of the atomic vibrations contribution in the low-temperature heat capacity of the system is analyzed.Comment: 14 pages, 7 figure