The collision of two-kinks defects

We have investigated the head-on collision of a two-kink and a two-antikink pair that arises as a generalization of the $\phi^4$ model. We have evolved numerically the Klein-Gordon equation with a new spectral algorithm whose accuracy and convergence were attested by the numerical tests. As a general result, the two-kink pair is annihilated radiating away most of the scalar field. It is possible the production of oscillons-like configurations after the collision that bounce and coalesce to form a small amplitude oscillon at the origin. The new feature is the formation of a sequence of quasi-stationary structures that we have identified as lump-like solutions of non-topological nature. The amount of time these structures survives depends on the fine-tuning of the impact velocity.Comment: 14 pages, 9 figure

Dual descriptions of spin two massive particles in D=2+1D=2+1 via master actions

In the first part of this work we show the decoupling (up to contact terms) of redundant degrees of freedom which appear in the covariant description of spin two massive particles in $D=2+1$. We make use of a master action which interpolates, without solving any constraints, between a first, second and third order (in derivatives) self-dual model. An explicit dual map between those models is derived. In our approach the absence of ghosts in the third order self-dual model, which corresponds to a quadratic truncation of topologically massive gravity, is due to the triviality (no particle content) of the Einstein-Hilbert action in $D=2+1$. In the second part of the work, also in $D=2+1$, we prove the quantum equivalence of the gauge invariant sector of a couple of self-dual models of opposite helicities (+2 and -2) and masses $m_+$ and $m_-$ to a generalized self-dual model which contains a quadratic Einstein-Hilbert action, a Chern-Simons term of first order and a Fierz-Pauli mass term. The use of a first order Chern-Simons term instead of a third order one avoids conflicts with the sign of the Einstein-Hilbert action.Comment: title and abstract slightly modified, 3 references added, comments on interactions include

News out of the old: the evolving technological incoherence of the world's largest companies

Large established companies from a variety of industrial sectors typically show a highly diversified knowledge base. A number of authors have found that this phenomenon can be measured using several technological indicators such as educational data on engineering backgrounds and patent applications (Granstrand and Sjölander, 1990; Patel and Pavitt 1994). The interesting feature of this trend is that companies invest to acquire competence in areas that are unrelated to their production specialisation in the market. However, this paradoxical empirical pattern is more easily observed than explained. Recently, some explanations have been put forward, one of which is that large innovative firms need to internalise many different branches of engineering knowledge in order to cope with uneven rates of development in the components they rely on (Brusoni et al. 2001). This work draws on the insights of the multi-technology corporation literature (e.g. Granstrand et al. 1997) and attempts to complement previous findings with a focus on the dynamic features of technological diversification. The chapter has two main goals: to draw a map of the rate and direction of technological diversification and, on this basis, to nourish a tentative discussion of the forces behind the evolving profile of multi-technology firms. In order to do this we use patent counts and classifications based on the SPRU database for nearly 500 of the world’s largest innovating companies from 1980 to 1996, as ranked by sales revenues. Large companies exhibit significant command of technologies unrelated to the actual making of their principal product lines, i.e., they reveal a degree of technological diversity or ‘incoherence’ as it is labelled throughout this chapter. Having underlined this contemporary stylised fact, we shall be concerned with the existence of broad changes in the rate and direction of technological diversification across and within industries. We find evidence of an emergent reorganization in corporate technological portfolios. Although the extent to which companies patent outside their core technical fields has remained stable, or even decreased slightly, the composition of the in-house technological mix appears to have changed considerably over a period of less than two decades. The technologies attracting the diversification movement in corporate capabilities, as revealed by patents, have increasingly become information & communication technologies (ICT), new materials and drugs & bioengineering. This is not entirely surprising since these technologies are commonly regarded as ‘generic technologies’ or ‘general purpose-technologies’. However, this tendency coincides with a remarkable regularity: for these three technology groups, the growth in patents was consistently higher for non-specialist sectors than for specialist sectors. Taken together, these findings can be interpreted as evidence that ‘new economy’ technology fields have gained weight against ‘older’ technologies, like the chemicals and mechanical fields, within the large established companies of the ‘old economy’. The observed patent regularities raise other issues. In particular, they could provide a useful perspective to an ongoing debate on whether the rise of new technologies has been associated with the substitution of or, on the contrary, complementarity with, older technologies. While there is considerable inter-industry diversity, the pattern of growth in ICT, materials and drugs & bioengineering patent groups seems to suggest that there is room for both stories. What is the meaning of this set of changes? On a macroscopic perspective we suggest these developments can be understood as an expression of an ongoing technological revolution in the neo- Schumpeterian sense of Freeman and Louçã (2001). As this paper has a more detailed perspective, we concentrate on the discussion of the strategic rationale behind the dynamics of diversification in the corporate knowledge base. At this stage we offer two intertwined hypotheses that fit with the observations. The chapter begins by addressing the empirical and conceptual contributions of the literature on technological diversification. Section 3 describes the data set and considers the methodological conditions necessary for a prudent use of patents as indicators of technological capabilities. Section 4 then reports on the analysis of our sample, which constitutes the core of the chapter. Section 5 critically assesses the empirical results, discusses implications for technology management and suggests some unsettled questions for innovation studies. The last section, Section 6, forms the conclusion

Futures research at DaimlerChrysler: socio-technology at the core of the corporate knowledge system

In today’s globalising and turbulent economy the way to achieve long-term leading position has become an increasingly tough dynamic process. Because a company’s market position is not safe for long if it systematically fails to keep up with the pace of change, sustaining competitive advantage is a continuous and restless task at the heart of which technological and organisational innovations prove fundamental. As in any other large business organisation, strategic planning at DaimlerChrysler (DC) is an activity of vital importance. The creation and renovation of a company’s competencies, i.e., its ability to master knowledge about production and distribution and its understanding of demand and users’ needs, has become itself institutionalised as a business of a particular trade. Most of the world’s leading corporations have a Research & Development (R&D) department where new science-based ideas and designs are tested and applied to the resolution of specific technological problems. Only more recently some large companies are carrying the internal division of labour a step further by establishing a new department or division exclusively devoted to socio-economic and strategic research. These units have the job of assessing the possible future directions of the organization in contrast with where the accumulation of competencies is leading. In this contribution we supply a description of the ways in which Society and Technology Research Group (STRG), the research and consulting institution within the DaimlerChrysler business group, helps strategic policy-making through the scenario methodology. We also aim at producing more general comments about the implications of the scenario-building process for managerial competence. Specifically, we elaborate on the analogy between R&D and futures research and argue that complex methodologies of interactive learning such as scenarios can be regarded as socio-technology. We also point out the significant role social sciences can be play in the process of generating useful knowledge for corporate management. The empirical base of this research is mainly composed by documentation provided by STRG and by an interview carried out with Frank Ruff, one of its senior managers. This evidence is compounded by reference to complementary data, namely from the case of Royal Dutch/Shell and its group-planning unit

Static potential in scalar QED3_3 with non-minimal coupling

Here we compute the static potential in scalar $QED_3$ at leading order in $1/N_f$. We show that the addition of a non-minimal coupling of Pauli-type (\eps j^{\mu}\partial^{\nu}A^{\alpha}), although it breaks parity, it does not change the analytic structure of the photon propagator and consequently the static potential remains logarithmic (confining) at large distances. The non-minimal coupling modifies the potential, however, at small charge separations giving rise to a repulsive force of short range between opposite sign charges, which is relevant for the existence of bound states. This effect is in agreement with a previous calculation based on M$\ddot{o}$ller scattering, but differently from such calculation we show here that the repulsion appears independently of the presence of a tree level Chern-Simons term which rather affects the large distance behavior of the potential turning it into constant.Comment: 13 pages, 3 figure