Innovation in Creative Industries: From the Quadruple Helix Model to the Systems Theory

Knowledge and creativity have always played a key role in the economy. Since the 2000s, the relevance of the creative industries, a high growth sector, has been pointed out as long as its strong and positive effects on jobs and economic growth. In the current context of rapid globalization and technological development, the innovation system is getting even more complex because it implies a shift in research focus from the supply to the demand side environment (consumption-driven economy). The authors focus on theoretical approaches coming from management and media studies able to explain the current paradigm shift in innovation and knowledge production and use: the Triple Helix model (and its developments) and Systems Theory. As an interesting case study, the Creative Enterprise Australia (CEA) is analyzed according the theoretical approaches shown. The paper tries to shed new light on the evolving role of knowledge pointing out the overlapping relationships between all the actors involved and the interpenetration of systems, and the prominent appointment of the media as an interpretative framework of the convergence of the depicted theories

Closure of Macroscopic Laws in Disordered Spin Systems: A Toy Model

We use a linear system of Langevin spins with disordered interactions as an exactly solvable toy model to investigate a procedure, recently proposed by Coolen and Sherrington, for closing the hierarchy of macroscopic order parameter equations in disordered spin systems. The closure procedure, based on the removal of microscopic memory effects, is shown to reproduce the correct equations for short times and in equilibrium. For intermediate time-scales the procedure does not lead to the exact equations, yet for homogeneous initial conditions succeeds at capturing the main characteristics of the flow in the order parameter plane. The procedure fails in terms of the long-term temporal dependence of the order parameters. For low energy inhomogeneous initial conditions and near criticality (where zero modes appear) deviations in temporal behaviour are most apparent. For homogeneous initial conditions the impact of microscopic memory effects on the evolution of macroscopic order parameters in disordered spin systems appears to be mainly an overall slowing down.Comment: 14 pages, LateX, OUTP-94-24

On Damage Spreading Transitions

We study the damage spreading transition in a generic one-dimensional stochastic cellular automata with two inputs (Domany-Kinzel model) Using an original formalism for the description of the microscopic dynamics of the model, we are able to show analitically that the evolution of the damage between two systems driven by the same noise has the same structure of a directed percolation problem. By means of a mean field approximation, we map the density phase transition into the damage phase transition, obtaining a reliable phase diagram. We extend this analysis to all symmetric cellular automata with two inputs, including the Ising model with heath-bath dynamics.Comment: 12 pages LaTeX, 2 PostScript figures, tar+gzip+u

Replica Symmetry Breaking in Attractor Neural Network Models

The phenomenon of replica symmetry breaking is investigated for the retrieval phases of Hopfield-type network models. The basic calculation is done for the generalized version of the standard model introduced by Horner [1] and by Perez-Vicente and Amit [2] which can exhibit low mean levels of neural activity. For a mean activity $\bar a =1/2$ the Hopfield model is recovered. In this case, surprisingly enough, we cannot confirm the well known one step replica symmetry breaking (1RSB) result for the storage capacity which was presented by Crisanti, Amit and Gutfreund [3] (\alpha_c^{\hbox{\mf 1RSB}}\simeq 0.144). Rather, we find that 1RSB- and 2RSB-Ans\"atze yield only slightly increased capacities as compared to the replica symmetric value (\alpha_c^{\hbox{\mf 1RSB}}\simeq 0.138\,186 and \alpha_c^{\hbox{\mf 2RSB}}\simeq 0.138\,187 compared to \alpha_c^{\hbox{\mf RS}}\simeq 0.137\,905), significantly smaller also than the value \alpha_c^{\hbox{\mf sim}} = 0.145\pm 0.009 reported from simulation studies. These values still lie within the recently discovered reentrant phase [4]. We conjecture that in the infinite Parisi-scheme the reentrant behaviour disappears as is the case in the SK-spin-glass model (Parisi--Toulouse-hypothesis). The same qualitative results are obtained in the low activity range.Comment: Latex file, 20 pages, 8 Figures available from the authors upon request, HD-TVP-94-

A vortex description of the first-order phase transition in type-I superconductors

Using both analytical arguments and detailed numerical evidence we show that the first order transition in the type-I 2D Abelian Higgs model can be understood in terms of the statistical mechanics of vortices, which behave in this regime as an ensemble of attractive particles. The well-known instabilities of such ensembles are shown to be connected to the process of phase nucleation. By characterizing the equation of state for the vortex ensemble we show that the temperature for the onset of a clustering instability is in qualitative agreement with the critical temperature. Below this point the vortex ensemble collapses to a single cluster, which is a non-extensive phase, and disappears in the absence of net topological charge. The vortex description provides a detailed mechanism for the first order transition, which applies at arbitrarily weak type-I and is gauge invariant unlike the usual field-theoretic considerations, which rely on asymptotically large gauge coupling.Comment: 4 pages, 6 figures, uses RevTex. Additional references added, some small corrections to the tex

Is trivial the antiferromagnetic RP(2) model in four dimensions?

We study the antiferromagnetic RP(2) model in four dimensions. We find a second order transition with two order parameters, one ferromagnetic and the other antiferromagnetic. The antiferromagnetic sector has mean-field critical exponents and a renormalized coupling which goes to zero in the continuum limit. The exponents of the ferromagnetic channel are not the mean-field ones, but the difference can be interpreted as logarithmic corrections. We perform a detailed analysis of these corrections and conclude the triviality of the continuum limit of this model.Comment: 21 pages, 5 figures, LaTeX2

The Ginzburg regime and its effects on topological defect formation

The Ginzburg temperature has historically been proposed as the energy scale of formation of topological defects at a second order symmetry breaking phase transition. More recently alternative proposals which compute the time of formation of defects from the critical dynamics of the system, have been gaining both theoretical and experimental support. We investigate, using a canonical model for string formation, how these two pictures compare. In particular we show that prolonged exposure of a critical field configuration to the Ginzburg regime results in no substantial suppression of the final density of defects formed. These results dismiss the recently proposed role of the Ginzburg regime in explaining the absence of topological defects in 4He pressure quench experiments.Comment: 8 pages, 5 ps figure

Fluctuating diamagnetism in underdoped high temperature superconductors

The fluctuation induced diamagnetism of underdoped high temperature superconductors is studied in the framework of the Lawrence-Doniach model. By taking into account the fluctuations of the phase of the order parameter only, the latter reduces to a layered XY-model describing a liquid of vortices which can be either thermally excited or induced by the external magnetic field. The diamagnetic response is given by a current-current correlation function which is evaluated using the Coulomb gas analogy. Our results are then applied to recent measurements of fluctuation diamagnetism in underdoped YBCO. They allow to understand both the observed anomalous temperature dependence of the zero-field susceptibility and the two distinct regimes appearing in the magnetic field dependence of the magnetization.Comment: 12 pages, 4 figures included, accepted for publication in PR

Nature of the Low Field Transition in the Mixed State of High Temperature Superconductors

We have numerically studied the statics and dynamics of a model three-dimensional vortex lattice at low magnetic fields. For the statics we use a frustrated 3D XY model on a stacked triangular lattice. We model the dynamics as a coupled network of overdamped resistively-shunted Josephson junctions with Langevin noise. At low fields, there is a weakly first-order phase transition, at which the vortex lattice melts into a line liquid. Phase coherence parallel to the field persists until a sharp crossover, conceivably a phase transition, near $T_{\ell} > T_m$ which develops at the same temperature as an infinite vortex tangle. The calculated flux flow resistivity in various geometries near $T=T_{\ell}$ closely resembles experiment. The local density of field induced vortices increases sharply near $T_\ell$, corresponding to the experimentally observed magnetization jump. We discuss the nature of a possible transition or crossover at $T_\ell$(B) which is distinct from flux lattice melting.Comment: Updated references. 46 pages including low quality 25 eps figures. Contact [email protected] or visit http://www.physics.ohio-state.edu:80/~ryu/ for better figures and additional movie files from simulations. To be published in Physical Review B1 01Jun9

Periodic vacuum and particles in two dimensions

Different dynamical symmetry breaking patterns are explored for the two dimensional phi4 model with higher order derivative terms. The one-loop saddle point expansion predicts a rather involved phase structure and a new Gaussian critical line. This vacuum structure is corroborated by the Monte Carlo method, as well. Analogies with the structure of solids, the density wave phases and the effects of the quenched impurities are mentioned. The unitarity of the time evolution operator in real time is established by means of the reflection positivity.Comment: Final version, additional references and the proof of reflection positivity added, 41 pages, 16 figure