1,720,987 research outputs found
On the massive Sine--Gordon equation in the first few regions of collapse
No full textWe study the ultraviolet stability problem for the two-dimensional Yukawa
interaction in the region
where . The results
have a natural Coulomb gas, interpretation, because the counterterms do not
depend on the field
ON THE ANALYTICITY OF THE PRESSURE IN THE HIERARCHICAL DIPOLE GAS
No full textThe convergence of the Mayer expansion is proved by estimating directly the convergence radius
Perturbation theory of the Fermi surface in a quantum liquid. A general quasiparticle formalism and one-dimensional systems.
Full text linkWe develop a perturbation theory formalism for the theory of the Fermi surface in a Fermi liquid of particles interacting via a bounded short range repulsive pair potential. The formalism is based on the renormalization group and provides a formal expansion of the large distance Schwinger functions in terms of a family of running couplings consisting of a one and two body quasi particle potentials. The flow of the running couplings is described in terms of a beta function, which is studied to all orders of perturbation theory and shown to obey, in the n–th order, n! bounds.......
Beta function and Schwinger functions for a many body system in one dimension. Anomaly of the Fermi surface
No full textWe present a rigorous discussion of the analyticity
properties of the beta function and of the effective potential for the
theory of the ground state of a one dimensional system of many spinless
fermions. We show that their analyticity domain as a function of the
running couplings is a polydisk with positive radius bounded below,
uniformly in all the cut offs (infrared and ultraviolet) necessary to
give a meaning to the formal Schwinger functions. We also prove the
vanishing of the scale independent part of the beta function showing
that this implies the analyticity of the effective potential and of the
Schwinger functions in terms of the bare coupling. Finally we show that
the pair Schwinger function has an anomalous long distance behaviour
Elliptic equations and gaussian processes
No full textWe consider a Gaussian process on the space of distributions generated
by a polynomial in the Laplace operator. We prove some support properties
for . As a byproduct we strenghten earlier results on the stochastic
Dirichlet problem on bounded regions . We describe in
this way the conditional -distribution of the restriction to
od a distribution , supposing that is known outside
: a somewhat detailed description of the sinularity of
in is given
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Renormalization-group approach to the theory of the Fermi surface
Full text linkWe describe an approach to the theory of the Fermi surface based on the renormalization group. A notion of quasi particle appears naturally in the theory. The beta function is finite to all orders of perturbation theory and we compute and discuss it to second order.
The normality of the Fermi surface is linked to the repulsivity of the quasi particle potential: the remarkable cancellations that occur in the beta function lead to think that a normal Fermi surface can perhaps occur, but only when the interaction between the quasi particles is repulsive. The approach was first proposed in an earlier paper, [BG1], and we give here an improved version of it, referring to [BG1] only to make use of technical estimates derived there
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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