1,721,522 research outputs found
Nontrivial fixed points and screening in the hierarchical two-dimensional Coulomb gas.
Full text linkWe show the existence and asymptotic stability of two fixed points of the renormalization group transformation for the hierarchical two-dimensional Coulomb gas in the sine-Gordon representation and temperatures slightly greater than the critical one. We prove also that the correlations at the fixed points decay as in the hierarchical massive scalar free field theory, that is as . We argue that this is the natural definition of screening in the hierarchical approximation
Prefazione
No full textPrefazione al volume curato dagli autori dedicato al centenario della Relatività Speciale di Einstein, con catalogo della Mostra Internazionale (Berlino, Gerusalemme) e saggi di vari autori italiani e stranier
The Renaissance of General Relativity in Context: A Historiographical Review
No full textIn the past years, a complex historical debate has emerged on the causes, origins, and manifestations of the process dubbed as the renaissance of Einstein’s theory of gravitation. After a thirty-year period of stagnation of the theory, known as its low-water-mark phase, the renaissance marks the post–World War II return of general relativity to the mainstream of physics. As an introduction to The Renaissance of General Relativity in Context, we discuss the various historical hypotheses that have been advanced and put them in dialogue with the chapters published in the volume. In discussing these studies, we argue that our previous interpretation of the renaissance process (as resulting from the interplay of social and epistemic factors) has been substantially confirmed. In addition, these studies enable our interpretation of the renaissance of general relativity to be redefined as a two-step process. A first phase of theoretical renaissance, driven by social transformations, occurred between the mid-1950s and the early 1960s and transformed the general theory of relativity into a bona fide physical theory. The second phase of this process, which we call the astrophysical turn, was an experiment-driven shift toward relativistic astrophysics and physical cosmology and was strongly related to discoveries in the astrophysical domain in the 1960s
Gravitational Waves and the Long Relativity Revolution
No full textThe recent discovery of gravitational waves is often seen as the confirmation of a prediction Einstein made one century ago. We argue instead that only after conceptual advances in general relativity between the mid-1950s and the early 1960s could such a prediction be made on the basis of unambiguous notions shared by a community of specialists. The conceptual transformation and the reorganization of knowledge related to general relativity that characterized this post-Second World War period can be used to properly understand the hitherto vaguely defined ‘renaissance of general relativity’. During its first phase, theoreticians took a conservative turn by refocusing on general relativity, after previously having worked on other research agendas mostly targeted at substituting general relativity with a superior theory. This turn was followed by a second phase that was characterized by a plurality of approaches to general relativity, which had in common the fact that they were able to develop intrinsically (generally) relativistic concepts, in particular radiation, rather than using other theories as an interpretative crutch
The reinvention of general relativity : a historiographical framework for assessing one hundred years of curved space-time
Full text linkThe history of the theory of general relativity presents unique features. After its discovery, the theory was immediately confirmed and rapidly changed established notions of space and time. The further implications of general relativity, however, remained largely unexplored until the mid 1950s, when it came into focus as a physical theory and gradually returned to the mainstream of physics. This essay presents a historiographical framework for assessing the history of general relativity by taking into account in an integrated narrative intellectual developments, epistemological problems, and technological advances; the characteristics of post-World War II and Cold War science; and newly emerging institutional settings. It argues that such a framework can help us understand this renaissance of general relativity as a result of two main factors: the recognition of the untapped potential of general relativity and an explicit effort at community building, which allowed this formerly disparate and dispersed field to benefit from the postwar changes in the scientific landscape
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
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