Birefringent Electroweak Textures

The behaviour of electromagnetic waves propagating through an electroweak homilia string network is examined. This string network is topologically stable as a cosmic texture, and is characterized by the spatial variation of the isospin rotation of the Higgs field. As a consequence the photon field couples to the intermediate vector bosons, producing a finite range electromagnetic field. It is found that the propagation speed of the photon depends on its polarization vector, whence an homilia string network acts as a birefringent medium. We estimate the birefringent scale for this texture and show that it depends on the frequency of the electromagnetic wave and the length scale of the homilia string network.Comment: 10 page

Revisiting the Impact of System Use on Task Performance: An Exploitative-Explorative System Use Framework

How information systems impact task performance has attracted a significant amount of attention from information systems researchers and generated high interest among practitioners. A commonly accepted view is that the potential of information systems must be realized through system use. Nevertheless, existing findings regarding the impact of system use on task performance are not yet conclusive. We attributed this to the various conceptualizations of system use and the unclear mechanisms through which system use influences task performance. Thus, this research attempts to create a better understanding of how system use influences task performance. To this end, we developed an exploitative-explorative system use framework in order to reconcile the various conceptualizations of system use and to depict how both exploitative and explorative system use influences task performance through impacting task innovation, management control, and task productivity. We created an instantiation of the framework using USAGE (exploitative system use) and adaptive system use (ASU, explorative system use). We conducted two empirical studies involving two different populations and using two different technologies. The first study consisted of 212 experienced users of MS Office, whereas the second study employed 372 new users of a video-editing tool. Our findings offer insight into how exploitative system use and explorative system use independently and jointly influence task performance constructs and also have implications for research and practices

Stability of string defects in models of non-Abelian symmetry breaking

In this paper we describe a new type of topological defect, called a homilia string, which is stabilized via interactions with the string network. Using analytical and numerical techniques, we investigate the stability and dynamics of homilia strings, and show that they can form stable electroweak strings. In SU(2)xU(1) models of symmetry breaking the intersection of two homilia strings is identified with a sphaleron. Due to repulsive forces, the homilia strings seperate, resulting in sphaleron annihilation. It is shown that electroweak homilia string loops cannot stabilize as vortons, which circumvents the adverse cosmological problems associated with stable loops. The consequences for GUT scale homilia strings are also discussed.Comment: 15 pages, revtex, with 8 figures. Submitted to PR