427 research outputs found
Collective Interaction-Driven Ratchet for Transporting Flux Quanta
We propose and study a novel way to produce a DC transport of vortices when
applying an AC electrical current to a sample. Specifically, we study
superconductors with a graduated random pinning density, which transports
interacting vortices as a ratchet system. We show that a ratchet effect appears
as a consequence of the long range interactions between the vortices. The
pinned vortices create an asymmetric periodic flux density profile, which
results in an asymmetric effective potential for the unpinned interstitial
vortices. The latter exhibit a net longitudinal rectification under an applied
transverse AC electric current.Comment: 4 pages, 5 postscript figure
Electronic structure of multiquantum giant vortex states in mesoscopic superconducting disks
We report self-consistent calculations of the microscopic electronic
structure of the so-called giant vortex states. These novel multiquantum vortex
states, detected by recent magnetization measurements on submicron disks, are
qualitatively different from the Abrikosov vortices in the bulk. We find that,
in addition to multiple branches of bound states in the core region, the local
tunneling density of states exhibits Tomasch oscillations due to the
single-particle interference arising from quantum confinement. These features
should be directly observable by scanning tunneling spectroscopy.Comment: 5 pages, 4 figure
Militant Extremist Mindset in Post-conflict Regions of the Balkans
This study explores the structure of Militant Extremist Mindset (MEM) within a sample of participants living in areas with enhanced risk of intergroup conflict. We were also interested in comparing members of three different ethnic groups (Serbs, Albanians, and Bosniaks) on MEM measures. A short version of the MEM scale was created for future use. We found that the factorial structure of MEM was replicated in the sample composed of people from both sides of a conflict. Ethnic groups did not differ significantly on the Grudge component of MEM. Group differences were pronounced on the Pro-violence and Utopianism factors. Albanians scored higher than Bosniaks and Serbs on these two dimensions. However, significant differences were obtained on the Ethos of Conflict (EOC) factor when groups of Serbs living within and outside areas of recent conflict were compared
Phase Fluctuations and Pseudogap Properties: Influence of Nonmagnetic Impurities
The presence of nonmagnetic impurities in a 2D ``bad metal'' depresses the
superconducting Berezinskii-Kosterlitz-Thouless transition temperature, while
leaving the pairing energy scale unchanged. Thus the region of the pseudogap
non-superconducting phase, where the modulus of the order parameter is non-zero
but its phase is random, and which opens at the pairing temperature is
substantially bigger than for the clean system. This supports the premise that
fluctuations in the phase of the order parameter can in principle describe the
pseudogap phenomena in high- materials over a rather wide range of
temperatures and carrier densities. The temperature dependence of the bare
superfluid density is also discussed.Comment: 11 pages, LaTeX, 1 EPS figure; final version to appear in
Low.Temp.Phy
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