Tunable diffusion of magnetic particles in a quasi-one-dimensional channel

The diffusion of a system of ferromagnetic dipoles confined in a quasi-one-dimensional parabolic trap is studied using Brownian dynamics simulations. We show that the dynamics of the system is tunable by an in-plane external homogeneous magnetic field. For a strong applied magnetic field, we find that the mobility of the system, the exponent of diffusion and the crossover time among different diffusion regimes can be tuned by the orientation of the magnetic field. For weak magnetic fields, the exponent of diffusion in the subdiffusive regime is independent of the orientation of the external field.Comment: 9 pages, 13 figures, to appear in Phys. Rev. E (2013

Structure of potentials with NN Higgs doublets

Extensions of the Standard Model with $N$ Higgs doublets are simple extensions presenting a rich mathematical structure. An underlying Minkowski structure emerges from the study of both variable space and parameter space. The former can be completely parametrized in terms of two future lightlike Minkowski vectors with spatial parts forming an angle whose cosine is $-(N-1)^{-1}$. For the parameter space, the Minkowski parametrization enables one to impose sufficient conditions for bounded below potentials, characterize certain classes of local minima and distinguish charge breaking vacua from neutral vacua. A particular class of neutral minima presents a degenerate mass spectrum for the physical charged Higgs bosons.Comment: 11 pages. Revtex4. Typos corrected. Few comments adde

Hysteresis and re-entrant melting of a self-organized system of classical particles confined in a parabolic trap

A self-organized system composed of classical particles confined in a two-dimensional parabolic trap and interacting through a potential with a short-range attractive part and long-range repulsive part is studied as function of temperature. The influence of the competition between the short-range attractive part of the inter-particle potential and its long-range repulsive part on the melting temperature is studied. Different behaviors of the melting temperature are found depending on the screening length ($\kappa$) and the strength ($B$) of the attractive part of the inter-particle potential. A re-entrant behavior and a thermal induced phase transition is observed in a small region of ($\kappa,B$)-space. A structural hysteresis effect is observed as a function of temperature and physically understood as due to the presence of a potential barrier between different configurations of the system.Comment: 8 pages, 6 figure

Evolution of Universe to the present inert phase

We assume that current state of the Universe can be described by the Inert Doublet Model, containing two scalar doublets, one of which is responsible for EWSB and masses of particles and the second one having no couplings to fermions and being responsible for dark matter. We consider possible evolutions of the Universe to this state during cooling down of the Universe after inflation. We found that in the past Universe could pass through phase states having no DM candidate. In the evolution via such states in addition to a possible EWSB phase transition (2-nd order) the Universe sustained one 1-st order phase transition or two phase transitions of the 2-nd order.Comment: 19 pages, 3 figure

Co-designing the knowledge management model

This work-in-progress study reviews co-designing processes through the lens of possibility-driven design (PDD). A knowledge management model (KMM) is co-designed by facilitating the development work of senior and regional innovation actors who share ideas, experience and information in the development of smart products and services for an age-friendly smart living environment. The empirical part is divided into three stages: an orientation workshop, two panel meetings and three co-design and validation workshops where an appropriate knowledge management model is co-designed through iteration rounds. The first stage maps the regional innovation actors, relevant organisations in the region and data flows between all the parties. Ideas of suitable ways to manage knowledge are gathered from the panel meetings of the second stage and are methodologically supported by the strategic options development and analysis (SODA) approach. At the time of writing this paper, the third stage consisting of three workshops with appropriate iteration rounds is on-going. The findings of the study provide insights regarding the use of PDD activities with an inclusion of the SODA approach when facilitating the co-design of a KMM with a multi-professional group of experts. The study contributes to the theory of PDD by integrating systematic methodological aspects to it when working on complex problems.info:eu-repo/semantics/publishedVersio