43,870 research outputs found
Hidden-symmetry-protected topological phases on a one-dimensional lattice
We demonstrate the existence of topologically nontrivial phase in a
one-dimensional fermionic lattice system subjected to synthetic gauge fields,
which is beyond the standard Altland-Zirnbauer classification of topological
insulators. The topological phase can be characterized by the presence of
degenerate zero-mode edge states or a quantized Berry phase of the occupied
Bloch band. By analyzing symmetries of the system, we identify that the
topological phase and zero-mode edge states are protected by two hidden
symmetries. An extended model with hidden symmetry breaking is also studied in
order to reveal the effect of hidden symmetries on the symmetry protected
topological phase.Comment: 6 pages, 5 figure
Natural NMSSM confronting with the LHC7-8
The natural supersymmetry (SUSY) requires that stop, sbottom, and gluino be
around one TeV or lighter. By using the direct SUSY search bounds from both
ATLAS and CMS Collaborations, we examine the constraints on the natural SUSY in
the Next to Minimal Supersymmetric Standard Model (NMSSM). We consider two
cases of interpretations for the Higgs boson data: (1) the Standard Model (SM)
like Higgs boson is the lightest CP-even Higgs boson; (2) the SM like Higgs
boson is the second lightest CP-even Higgs boson. We find that the direct SUSY
searches at the LHC impose a strong constraint on the light gluino scenarios,
and in both cases the gluino can not be lighter than 1.1 TeV with sbottom mass
up to 600 GeV and stop mass up to 550 GeV.Comment: 43 pages, 13 figure
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