13 research outputs found
Twisted Superconducting Semilocal Strings
A new class of twisted, current carrying, stationary, straight string
solutions having finite energy per unit length is constructed numerically in an
extended Abelian Higgs model with global SU(2) symmetry. The new solutions
correspond to deformations of the embedded Abrikosov-Nielsen-Olesen (ANO)
vortices by a twist -- a relative coordinate dependent phase between the two
Higgs fields. The twist induces a global current flowing through the string,
and the deformed solutions bifurcate with the ANO vortices in the limit of
vanishing current. For each value of the winding number (determining
the magnetic flux through the plane orthogonal to the string) there are
distinct, two-parametric families of solutions. One of the continuously varying
parameters is the twist, or the corresponding current, the other one can be
chosen to be the momentum of the string. For fixed values of the momentum and
twist, the distinct solutions have different energies and can be viewed as
a lowest energy ``fundamental'' string and its ``excitations''
characterized by different values of their ``polarization''. The latter is
defined as the ratio of the angular momentum of the vortex and its momentum. In
their rest frame the twisted vortices have lower energy than the embedded ANO
vortices and could be of considerable importance in various physical systems
(from condensed matter to cosmic strings).Comment: 39 pages, 20 figure
Bogomolny equations for vortices in the noncommutative torus
We derive Bogomolny-type equations for the abelian Higgs model defined on the noncommutative torus and discuss its vortex like solutions. To this end, we carefully analyze how periodic boundary conditions have to be handled in noncommutative space and discuss how vortex solutions are constructed. We also consider the extension to an U(2) × U(1) model, a simplified prototype of the noncommutative standard model.Facultad de Ciencias Exacta
Gravitating Monopole Solutions II
We present analytical and numerical results for static, spherically symmetric
solutions of the Einstein Yang-Mills Higgs equations corresponding to magnetic
monopoles and non-abelian magnetically charged black holes. In the limit of
infinite Higgs mass we give an existence proof for these solutions. The
stability of the abelian extremal Reissner-Nordstrom black holes is reanalyzed.Comment: 24 pages, 11 figures (uuencoded compressed tar
Magnetic tweezers for intracellular applications
doi:10.1063/1.1599066 http://rsi.aip.org/rsinak/v74/i9/p4158_s1We have designed and constructed a versatile magnetic tweezer primarily for intracellular investigations. The micromanipulator uses only two coils to simultaneously magnetize to saturation micron-size superparamagnetic particles and generate high magnitude constant field gradients over cellular dimensions. The apparatus resembles a miniaturized Faraday balance, an industrial device used to measure magnetic susceptibility. The device operates in both continuous and pulse modes. Due to its compact size, the tweezers can conveniently be mounted on the stage of an inverted microscope and used for intracellular manipulations. A built-in temperature control unit maintains the sample at physiological temperatures. The operation of the tweezers was tested by moving 1.28 μm diameter magnetic beads inside macrophages with forces near 500 pN.This work was partially supported by the NSF ~Grant No. DBI-9730999!
Bogomolny equations for vortices in the noncommutative torus
We derive Bogomolny-type equations for the Abelian Higgs model defined on the
noncommutative torus and discuss its vortex like solutions. To this end, we
carefully analyze how periodic boundary conditions have to be handled in
noncommutative space and discussed how vortex solutions are constructed. We
also consider the extension to an model, a simplified
prototype of the noncommutative standard model.Comment: 23 pages, no figure