1,721,063 research outputs found
STRESS-ENERGY TENSOR AND ULTRAVIOLET BEHAVIOR IN MASSIVE INTEGRABLE QUANTUM-FIELD THEORIES
No full textThe short distance behavior of massive integrable quantum field theories is analyzed in terms of the form factor approach. We show that the on-shell dynamics is compatible with different definitions of the stress-energy tensor T(munu)(x) of the theory. In terms of form factors, this is equivalent to having a possible nonzero matrix element F1 of the trace of T(munu) on a one-particle state. Each choice of F1 induces a different scaling behavior of the massive theory in the ultraviolet limit
RANDOM BOND ISING-MODEL AND MASSLESS PHASE OF THE GROSS-NEVEU MODEL
No full textThe O(n) Gross-Neveu model for n < 2 presents a massless phase that can be characterized by right-left mover scattering processes. The limit n -->, O describes the on-shell properties of the random bond Ising model
Correlation functions in the two-dimensional Ising model in a magnetic field at T=T-c
No full textThe one and two-particle form factors of the energy operator in the two-dimensional Ising model in a magnetic field at are exactly computed within the form factor bootstrap approach. Together with the matrix elements of the magnetisation operator already computed in Nucl.Phys.B455:724-758,1995, they are used to write down the large distance expansion for the correlators of the two relevant fields of the model
Form Factors for Integrable Lagrangian Field Theories, the Sinh-Gordon Model
No full textUsing Watson's and the recursive equations satisfied by matrix elements of local operators in two-dimensional integrable models, we compute the form factors of the elementary field and the stress-energy tensor of Sinh-Gordon theory. Form factors of operators with higher spin or with different asymptotic behaviour can easily be deduced from them. The value of the correlation functions are saturated by the form factors with lowest number of particle terms. This is illustrated by an application of the form factors of the trace of to the sum rule of the -theorem
Form Factors of the Elementary Field in the Bullough-Dodd Model
No full textWe derive the recursive equations for the form factors of the local hermitian operators in the Bullough-Dodd model. At the self-dual point of the theory, the form factors of the fundamental field of the Bullough-Dodd model are equal to those of the fundamental field of the Sinh-Gordon model at a specific value of the coupling constant
Correlation functions along a massless flow
No full textA non-perturbative method based on the Form Factor bootstrap approach is proposed for the analysis of correlation functions of 2-D massless integrable theories and applied to the massless flow between the Tricritical and the Critical Ising Models
Statistical models with a line of defect
No full textThe factorization condition for the scattering amplitudes of an integrable model with a line of defect gives rise to a set of Reflection-Transmission equations. The solutions of these equations in the case of diagonal S-matrix in the bulk are only those with S= +/-1. The choice S = -1 corresponds to the Ising model. We compute the transmission and reflection amplitudes relative to the interaction of the Majorana fermion with the defect and we discuss their relevant features.The factorization condition for the scattering amplitudes of an integrable model with a line of defect gives rise to a set of Reflection-Transmission equations. The solutions of these equations in the case of diagonal -matrix in the bulk are only those with . The choice corresponds to the Ising model. We compute the transmission and reflection amplitudes relative to the interaction of the Majorana fermion with the defect and we discuss their relevant features
On the delay times of merging double neutron stars
Full text linkThe merging rate of double neutron stars (DNS) has a great impact on many astrophysical issues, including the interpretation of gravitational waves signals, of the short gamma-ray bursts (GRBs), and of the chemical properties of stars in galaxies. Such rate depends on the distribution of the delay times (DDT) of the merging events. In this paper, we derive a theoretical DDT of merging DNS following from the characteristics of the clock controlling their evolution. We show that the shape of the DDT is governed by a few key parameters, primarily the lower limit and the slope of the distribution of the separation of the DNS systems at birth. With a parametric approach, we investigate on the observational constraints on the DDT from the cosmic rate of short GRBs and the europium-to-iron ratio in Milky Way stars, taken as tracer of the products of the explosion. We find that the local rate of DNS merging requires that ∼ per cent of neutron stars progenitors live in binary systems which end their evolution as merging DNS within a Hubble time. The redshift distribution of short GRBs does not yet provide a strong constraint on the shape of the DDT, although the best-fitting models have a shallow DDT. The chemical pattern in Milky Way stars requires an additional source of europium besides the products from merging DNS, which weakens the related requirement on the DDT. At present both constraints can be matched with the same DDT for merging DNS
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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