3,199 research outputs found
A general approximation of quantum graph vertex couplings by scaled Schroedinger operators on thin branched manifolds
We demonstrate that any self-adjoint coupling in a quantum graph vertex can
be approximated by a family of magnetic Schroedinger operators on a tubular
network built over the graph. If such a manifold has a boundary, Neumann
conditions are imposed at it. The procedure involves a local change of graph
topology in the vicinity of the vertex; the approximation scheme constructed on
the graph is subsequently `lifted' to the manifold. For the corresponding
operator a norm-resolvent convergence is proved, with the natural
identification map, as the tube diameters tend to zero.Comment: 19 pages, one figure; introduction amended and some references added,
to appear in CM
Duality and Anholonomy in Quantum Mechanics of 1D Contact Interactions
We study systems with parity invariant contact interactions in one dimension.
The model analyzed is the simplest nontrivial one --- a quantum wire with a
point defect --- and yet is shown to exhibit exotic phenomena, such as strong
vs weak coupling duality and spiral anholonomy in the spectral flow. The
structure underlying these phenomena is SU(2), which arises as accidental
symmetry for a particular class of interactions.Comment: 4 pages ReVTeX with 4 epsf figures. KEK preprint 2000-3. Correction
in Eq.(14
Characterization of a novel reassortant H5N6 highly pathogenic avian influenza virus clade 2.3.4.4 in Korea, 2017
Nature of 45 degree vortex lattice reorientation in tetragonal superconductors
The transformation of the vortex lattice in a tetragonal superconductor which
consists of its 45 degree reorientation relative to the crystal axes is studied
using the nonlocal London model. It is shown that the reorientation occurs as
two successive second order (continuous) phase transitions. The transition
magnetic fields are calculated for a range of parameters relevant for
borocarbide superconductors in which the reorientation has been observed
Z(2)-Singlino Dark Matter in a Portal-Like Extension of the Minimal Supersymmetric Standard Model.
We propose a Z2-stabilized singlino () as a dark matter candidate in extended and R-parity violating versions of the supersymmetric standard model. interacts with visible matter via a heavy messenger field S, which results in a supersymmetric version of the Higgs portal interaction. The relic abundance of can account for cold dark matter if the messenger mass satisfies GeV. Our model can be implemented in many realistic supersymmetric models such as the next-to-minimal supersymmetric (SUSY) standard model and nearly minimal SUSY standard model
- …