1,721,034 research outputs found
ON THE POSSIBILITY OF ZN EXOTIC SUPERSYMMETRY IN 2-DIMENSIONAL CONFORMAL FIELD-THEORY
No full textWe investigate the possibility to construct extended parafermionic conformal algebras whose generating current has spin 1 + 1/K, generalizing the superconformal (spin 3/2) and the Fateev-Zamolodchikov (spin 4/3) algebras. Models invariant under such algebras would possess Z(K) exotic supersymmetries satisfying (supercharge)K = (momentum). However, we show that for K = 4 this new algebra allows only for models at c = 1, for K = 5 it is a trivial rephrasing of the ordinary Z5 parafermionic model, for K = 6,7 (and, requiring unitarity, for all larger K) such algebras do not exist. Implications of this result for existence of exotic supersymmetry in two-dimensional field theory are discussed
Entanglement entropy from corner transfer matrix in Forrester-Baxter non-unitary RSOS models
Get PDFUsing a corner transfer matrix approach, we compute the bipartite entanglement Ré nyi entropy in the off-critical perturbations of non-unitary conformal minimal models realised by lattice spin chains Hamiltonians related to the Forrester-Baxter RSOS models (Bianchini et al 2015 J. Stat. Mech. P03010) in regime III. This allows to show on a set of explicit examples that the Ré nyi entropies for non-unitary theories rescale near criticality as the logarithm of the correlation length with a coefficient proportional to the effective central charge. This complements a similar result, recently established for the size rescaling at the critical point (Bianchini et al 2015 J. Phys. A: Math. Theor. 48 04FT01), showing the expected agreement of the two behaviours. We also compute the first subleading unusual correction to the scaling behaviour, showing that it is expressible in terms of expansions of various fractional powers of the correlation length, related to the differences between the conformal dimensions of fields in the theory and the minimal conformal dimension. Finally, a few observations on the limit leading to the off-critical logarithmic minimal models of Pearce and Seaton (2012 J. Stat. Mech. P09014) are put forward
Addendum: Nonlinear integral equations for the sausage model (2017 J. Phys. A: Math. Theor. 50 314005)
Get PDFIn [1], here below referred as I, we have written the set of non-linear integral equations (NLIEs) governing the finite size effects of the vacuum as well as the thermodynamics for the integrable deformation of O(3) non-linear sigma model (NLSM), getting it from a manipulation, inspired by those introduced years ago by Suzuki [3, 4], of the larger set of Thermodynamic Bethe Ansatz (TBA) equations of the model, known since the original paper by Fateev, Onofri and Zamolodchikov [2]. However, one can realize that (I3.24)5, a crucial relation in our derivation of the sausage model NLIE, is not well-defined because neither Q nor Q ̄ are analytic on the real axis. Hence Q ̃ and Q ̃ ̄ cannot be interpreted as Fourier transforms along the real line. In this addendum we examine this problem carefully and show that the derivation of the sausage model NLIE remains valid in spite of this potential difficulty
The staircase model: massless flows and hydrodynamics
No full textThe staircase model (SM) is a simple generalization of the sinh-Gordon model, obtained by complexifying the coupling constant. This produces a new theory with many interesting features. Chief among them is the fact that scaling functions such as Zamolodchikov's c-function display 'roaming' behaviour, that is, they visit the vicinity of an infinite number of conformal fixed points, the unitary minimal models of conformal field theory. This rich structure also makes the model an interesting candidate for study using the generalized hydrodynamic approach to integrable quantum field theory (IQFT). By studying hydrodynamic quantities such as the effective velocities of quasiparticles we can develop a more physical picture of interaction in the theory, both at and away from equilibrium. Indeed, we find that in the SM the effective velocity displays monotonicity features not found in any other IQFT. These admit a natural interpretation when investigated in the context of the massless theories known as models, which provide an effective description of massless flows between consecutive unitary minimal models. Consequently, we find that the effective velocity in the SM can be reconstructed by a 'cut and paste' procedure involving the equivalent functions associated to the massless excitations of suitable models. We also investigate the average currents and densities of higher spin conserved quantities in the partitioning protocol
Nonlinear integral equations for the sausage model
No full textThe sausage model, first proposed by Fateev, Onofri, and Zamolodchikov, is a deformation of the O(3) sigma model preserving integrability. The target space is deformed from the sphere to sausage shape by a deformation parameter v. This model is defined by a factorizable S-matrix which is obtained by deforming that of the O(3) sigma model by a parameter . Clues for the deformed sigma model are provided by various UV and IR information through the thermodynamic Bethe ansatz (TBA) analysis based on the S-matrix. Application of TBA to the sausage model is, however, limited to the case of integer where the coupled integral equations can be truncated to a finite number. In this paper, we propose a finite set of nonlinear integral equations (NLIEs), which are applicable to generic value of . Our derivation is based on T-Q relations extracted from the truncated TBA equations. For a consistency check, we compute next-leading order corrections of the vacuum energy and extract the S-matrix information in the IR limit. We also solved the NLIE both analytically and numerically in the UV limit to get the effective central charge and compared with that of the zero-mode dynamics to obtain exact relation between v and
Irreversibility of the renormalization group flow in non-unitary quantum field theory
Get PDFWe show irreversibility of the renormalization group flow in non-unitary but PT -invariant quantum field theory in two space-time dimensions. In addition to unbroken PT -symmetry and a positive energy spectrum, we assume standard properties of quantum field theory including a local energy-momentum tensor and relativistic invariance. This generalizes Zamolodchikov’s ctheorem to PT -symmetric hamiltonians. Our proof follows closely Zamolodchikov’s arguments. We show that a function ceff(s) of the renormalization group parameter s exists which is nonnegative and monotonically decreasing along renormalization group flows. Its value at a critical point is the “effective central charge” entering the specific free energy. At least in rational models, this equals ceff = c − 24∆, where c is the central charge and ∆ is the lowest primary field dimension in the conformal field theory which describes the critical point
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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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