Information-entropic analysis of Korteweg--de Vries solitons in the quark-gluon plasma

Solitary waves propagation of baryonic density perturbations, ruled by the Korteweg--de Vries equation in a mean-field quark-gluon plasma model, are investigated from the point of view of the theory of information. A recently proposed continuous logarithmic measure of information, called configurational entropy, is used to derive the soliton width, defining the pulse, for which the informational content of the soliton spatial profile is more compressed, in the Shannon's sense.Comment: 6 pages, 1 figur

Coherent phonon transport in short-period two-dimensional superlattices of graphene and boron nitride

Promoting coherent transport of phonons at material interfaces is a promising strategy for controlling thermal transport in nanostructures and an alternative to traditional methods based on structural defects. Coherent transport is particularly relevant in short-period heterostructures with smooth interfaces and long-wavelength heat-carrying phonons, such as two-dimensional superlattices of graphene and boron nitride. In this work, we predict phonon properties and thermal conductivities in these superlattices using a normal mode decomposition approach. We study the variation of the frequency dependence of these properties with the periodicity and interface configuration (zigzag and armchair) for superlattices with period lengths within the coherent regime. Our results showed that the thermal conductivity decreases significantly from the first period length (0.44 nm) to the second period length (0.87 nm), 13% across the interfaces and 16% along the interfaces. For greater periods, the conductivity across the interfaces continues decreasing at a smaller rate of 11 W/mK per period length increase (0.43 nm), driven by changes in the phonon group velocities (coherent effects). In contrast, the conductivity along the interfaces slightly recovers at a rate of 2 W/mK per period, driven by changes in the phonon relaxation times (diffusive effects). By changing the interface configuration from armchair to zigzag, the conductivities for all period lengths increase by approximately 7% across the interfaces and 19% along the interfaces

Non-Associativity in the Clifford Bundle on the Parallelizable Torsion 7-Sphere

In this paper we discuss generalized properties of non-associativity in Clifford bundles on the 7-sphere S7. Novel and prominent properties inherited from the non-associative structure of the Clifford bundle on S7 are demonstrated. They naturally lead to general transformations of the spinor fields on S7 and have dramatic consequences for the associated Kac-Moody current algebras. All additional properties concerning the non-associative structure in the Clifford bundle on S7 are considered. We further discuss and explore their applications.Comment: 16 page

Matters for judgement: some thoughts on method in management history

Purpose: This paper reflects on some aspects of method in management history and the importance of the self-reflection on their world-view that must accompany authors’ endeavours, in order to be articulated in the matters they proffer for the reader’s judgement. Approach: Drawing on the insights proffered by Evans (1999:1) about how to study, research, write about and read history, this paper offers some thoughts on the importance of giving due consideration to method in management history. Research & Practical Implications: Thomas Hobbes (1660/1994:32) observed that “Out of our conception of the past, we make a future”. It behoves us then, as managers and management scholars, to be satisfied that our conceptions of the past are developed in ways that, as far as possible, avoid the problems that would make them less than useful in creating that future. This paper identifies some of the issues of which those seeking to create the future must be cognisant. Value: If knowing accurately the history of management thought is of importance to scholars and practitioners, then this paper alerts practitioners and commentators to the need for a sound method in producing, and learning from, the lessons of management history

Revising the ‘myth’ of a ‘clean wehrmacht’: generals’ trials, public opinion, and the dynamics of Vergangenheitsbewältigung in West Germany, 1948–60

Among one of the most consistent claims made by the organizers and supporters of the ‘Wehrmacht exhibition’ has been that the ‘myth’ of a ‘clean Wehrmacht’ took root in the Federal Republic of Germany in the early 1950s, lasting well into the 1980s, only to have been finally shattered by the exhibition itself in the mid-1990s. Although this thesis has very little to do with the actual content of the exhibition — which examined the role of the Wehrmacht, and the army in particular, in co-operating with SS units in the final solution in the Soviet Union, in executions of enemy personnel, and the extermination of countless civilians through the device of declaring them to be partisans — it is has been repeated consistently by a number of historians

Characterization of manifolds of constant curvature by spherical curves

It is known that the so-called rotation minimizing (RM) frames allow for a simple and elegant characterization of geodesic spherical curves in Euclidean, hyperbolic, and spherical spaces through a certain linear equation involving the coefficients that dictate the RM frame motion (da Silva, da Silva in Mediterr J Math 15:70, 2018). Here, we shall prove the converse, i.e., we show that if all geodesic spherical curves on a Riemannian manifold are characterized by a certain linear equation, then all the geodesic spheres with a sufficiently small radius are totally umbilical and, consequently, the given manifold has constant sectional curvature. We also furnish two other characterizations in terms of (i) an inequality involving the mean curvature of a geodesic sphere and the curvature function of their curves and (ii) the vanishing of the total torsion of closed spherical curves in the case of three-dimensional manifolds. Finally, we also show that the same results are valid for semi-Riemannian manifolds of constant sectional curvature.Comment: To appear in Annali di Matematica Pura ed Applicat

ELKO, flagpole and flag-dipole spinor fields, and the instanton Hopf fibration

In a previous paper we explicitly constructed a mapping that leads Dirac spinor fields to the dual-helicity eigenspinors of the charge conjugation operator (ELKO spinor fields). ELKO spinor fields are prime candidates for describing dark matter, and belong to a wider class of spinor fields, the so-called flagpole spinor fields, corresponding to the class-(5), according to Lounesto spinor field classification, based on the relations and values taken by their associated bilinear covariants. Such a mapping between Dirac and ELKO spinor fields was obtained in an attempt to extend the Standard Model in order to encompass dark matter. Now we prove that such a mapping, analogous to the instanton Hopf fibration map $S^3... S^7\to S^4$, prevents ELKO to describe the instanton, giving a suitable physical interpretation to ELKO. We review ELKO spinor fields as type-(5) spinor fields under the Lounesto spinor field classification, explicitly computing the associated bilinear covariants. This paper is also devoted to investigate some formal aspects of the flag-dipole spinor fields, which correspond to the class-(4) under the Lounesto spinor field classification. In addition, we prove that type-(4) spinor fields (corresponding to flag-dipoles) and ELKO spinor fields (corresponding to flagpoles) can also be entirely described in terms of the Majorana and Weyl spinor fields. After all, by choosing a projection endomorphism of the spacetime algebra Cl(1,3) it is shown how to obtain ELKO, flagpole, Majorana and Weyl spinor fields, respectively corresponding to type-(5) and -(6) spinor fields, uniquely from limiting cases of a type-(4) (flag-dipole) spinor field, in a similar result obtained by Lounesto.Comment: 17 Pages, RevTeX, accepted for publication in Adv. Appl. Clifford Al

Hempelian and Kuhnian approaches in the philosophy of medicine: the Semmelweis case

Semmelweis?s investigations of puerperal fever are some of the most interesting in the history of medicine. This paper considers Hempel?s (1966) analysis of the Semmelweis case. It argues that this analysis is inadequate and needs to be supplemented by some Kuhnian ideas. Kuhn?s notion of paradigm needs to be modified to apply to medicine in order to take account of the classification schemes involved in medical theorising. However with a suitable modification it provides an explanation of Semmelweis?s failure which is argued to be superior to some of the external reasons often given. Despite this success in applying Kuhn?s ideas to medicine, it is argued that these ideas must be further modified to take account of the fact that medicine is not a natural science but primarily a practice designed to prevent and cure diseases