Paul Ginsparg

First and second order phase transitions in gauge theories at finite temperature

Abstract We consider in general the nature of the phase transition which occurs in 4D gauge theories coupled to scalar and spinor fields at finite temperature. It is shown that the critical behavior can be isolated in an effective 3D theory of the zero frequency mode whose lagrangian may be calculated explicitly in weak coupling perturbation theory. This lagrangian, in turn, may be investigated by means of standard ϵ-expansion techniques. Theories with an asymptotically free gauge coupling constant possess no stable fixed point in the ϵ-expansion and are inferred to have weakly first-order phase transitions; theories not satisfying this condition may have second-order transitions.

Overview of the 2003 KDD Cup

This paper surveys the 2003 KDD Cup, a competition held in conjunction with the Ninth ACM SIGKDD International Conference on Knowledge Discovery and Data Mining (KDD) in August 2003. The competition focused on mining the complex real-life social network inherent in the e-print arXiv (arXiv.org). We describe the four KDD Cup tasks: citation prediction, download prediction, data cleaning, and an open task.

Strings on curved space-times: Black holes, torsion, and duality

Abstract We present a general discussion of strings propagating on noncompact coset spaces G/H in terms of gauged WZW models, emphasizing the role played by isometries in the existence of target-space duality. Fixed points of the gauged transformations induce metric singularities and, in the case of abelian subgroups H, become horizons in a dual geometry. We also give a classification of models with a single timelike coordinate together with an explicit list for dimensions D ⩽ 10. We study in detail the class of models described by the cosets SL(2, R ) ⊗ SO(1, 1) D −2 /SO(1, 1). For D ⩾ 2 each coset represent space-time geometries: (2d black hole) ⊗ R D−2 and (3d black string) ⊗ R D−3 with nonvanishing torsion. They are shown to be dual in such a way that the singularity of the former geometry (which is not due to a fixed point) is mapped to a regular surface (i.e. not even a horizon) in the latter. These cosets also lead to the conformal field theory description of known and new cosmological string models.

Plagiarism Detection in arXiv

We describe a large-scale application of methods for finding plagiarism in research document collections. The methods are applied to a collection of 284,834 documents collected by arXiv.org over a 14 year period, covering a few different research disciplines. The methodology efficiently detects a variety of problematic author behaviors, and heuristics are developed to reduce the number of false positives. The methods are also efficient enough to implement as a real-time submission screen for a collection many times larger.

(central charge c) = 1 SUPERCONFORMAL FIELD THEORY

We consider superconformal field theories with central charge c = 23c = 1. We find five continuous one-parameter families of theories all interconnected via a set of four multicritical points that are reached by modding out theories with enlarged symmetries. We find as well six theories that have no integrable marginal operators and thus constitute isolated points of superconformal invariance in the c = 1 moduli space. We briefly discuss c = 32 conformal theories that contain a twisted superconformal algebra, including three isolated theories with a twisted N = 3 superconformal algebra, and theories constructed as the tensor product of the c = 45 and c = 710 minimal theories.

Can Peer Review Be Better Focused

Summary If we were to start from scratch today to design a quality-controlled archive and distribution system for scientific and technical information, it could take a very different form from what has evolved in the past decade from pre-existing print infrastructure. Recent technological advances could provide not only more efficient means of accessing and navigating the information, but also more cost-effective means of authentication and quality control. This article discusses relevant experiences of the past decade from open electronic distribution of research materials in physics and related disciplines, and describes their implications for proposals to improve the implementation of peer review.

E-prints and journal articles in astronomy : a productive co-existence

Are the e‐prints (electronic preprints) from the arXiv repository being used instead of journal articles? We show that the e‐prints have not undermined the usage of journal papers from the four core journals in astrophysics. As soon as the journal article is published, the astronomical community prefers to read it and the use of e‐prints through the NASA Astrophysics Data System drops to zero. This suggests that most astronomers have access to institutional subscriptions and that they choose to read the journal article. In other words, the e‐prints have not undermined journal use in this community and thus currently do not pose a financial threat to publishers. Furthermore, we show that the half‐life (the point at which the use of an article drops to half the use of a newly published article) for an e‐print is shorter than for a journal paper.

Desperately Seeking Superstrings

We provide a detailed analysis of the problems and prospects of superstring theory c. 1986, anticipating much of the progress of the decades to follow.

Large q expansions for q-state gauge-matter Potts models in lagrangian form

Abstract We consider the lagrangian form of a q -state generalization of Ising gauge theories with matter fields in d = 3 and 4 dimensions. The theory is exactly soluble in the limit q → ∞ and corrections are easily calculable in power series in 1 q 1 d . Extrapolating the series for the free energies and latent heats by the method of Pade approximants, we have constructed the phase diagrams for all values of q . Our results agree well with known results for pure spin systems and, for the case q = 2, with Ising Monte Carlo data.

Mapping subsets of scholarly information

We illustrate the use of machine learning techniques to analyze, structure, maintain, and evolve a large online corpus of academic literature. An emerging field of research can be identified as part of an existing corpus, permitting the implementation of a more coherent community structure for its practitioners.