1,721,063 research outputs found
Crumpled Triangulations and Critical Points in 4D Simplicial Quantum Gravity
No full textWe estimate analytically the critical coupling separating the weak and the strong coupling
regime in 4D simplicial quantum gravity to be located at k~ tit '~ 1.3093. By carrying out a
detailed geometrical analysis of the strong coupling phase we argue that the distribution of
dynamical triangulations with singular vertices and singular edges, dominating in such a regime,
is characterized by distinct subdominating peaks. The presence of such peaks generates volumedependent
pseudo-critical points: kocrit(N4 = 32000) ~ 1.25795, k~rit(N4 = 48000) --~ 1.26752,
k~rit(N4 = 64000) '~ 1.27466, etc., which appear in good agreement with available Monte Carlo
data. Under a certain scaling hypothesis we analytically characterize the (canonical) average
value, cl (N4; k2) = (No)/N4, and the susceptibility, c2(N4; k2) = ((N 2) - (No)2)/N4, associated
with the vertex distribution of the 4D triangulations considered. Again, the resulting analytical
expressions are found in quite a good agreement with their Monte Carlo counterpart
The geometry of dynamical triangulations
No full textWe discuss the geometry of dynamical triangulations associated with 3-dimensional and 4-dimensional simplicial quantum gravity. We provide analytical expressions for the canonical partition function in both cases, and study its large volume behavior. In the space of the coupling constants of the theory, we characterize the infinite volume line and the associated critical points. The results of this analysis are found to be in excellent agreement with the MonteCarlo simulations of simplicial quantum gravity. In particular, we provide an analytical proof that simply-connected dynamically triangulated 4-manifolds undergo a higher order phase transition at a value of the inverse gravitational coupling given by 1.387, and that the nature of this transition can be concealed by a bystable behavior. A similar analysis in the 3-dimensional case characterizes a value of the critical coupling (3.845) at which hysteresis effects are present
Z2 GAUGE MATTER COUPLED TO 4-D SIMPLICIAL QUANTUM-GRAVITY
No full textAMBJORN J, JURKIEWICZ J, BILKE S, BURDA Z, Petersson B. Z2 GAUGE MATTER COUPLED TO 4-D SIMPLICIAL QUANTUM-GRAVITY. MODERN PHYSICS LETTERS A. 1994;9(27):2527-2541.Employing Monte-Carlo simulation we study the phase diagram of a Z2 gauge field coupled to simplicial quantum gravity. We localize a critical point of the model where both the matter and gravity sectors have a second order phase transition. We found the value of the critical index gamma(g) = 0.16(4) of the gravity susceptibility at the critical point
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
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
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