11,550 research outputs found
Search for single production of the vector-like top partner at the 14 TeV LHC
The new heavy vector-like top partner~() is one of typical features of
many new physics models beyond the standard model. In this paper we study the
discovery potential of the LHC for the vector-like -quark both in the
leptonic and (trilepton) channels at
TeV in the single production mode. Our analysis is based on a
simplified model including a singlet with charge with only two
free parameters, namely the coupling parameter and the top
partner mass . The exclusion limits, evidence and the
discovery reach in the parameter plane of , are,
respectively, obtained for some typical integrated luminosity at the 14 TeV
LHC. Finally we analyze the projected sensitivity in terms of the production
cross section times branching fraction for two decay channel.Comment: 15 pages, 10 figures, 2 tables. version in EPJ
Entanglement entropy and entanglement spectrum of the Kitaev model
In this paper, we obtain an exact formula for the entanglement entropy of the
ground state and all excited states of the Kitaev model. Remarkably, the
entanglement entropy can be expressed in a simple separable form S=S_G+S_F,
with S_F the entanglement entropy of a free Majorana fermion system and S_G
that of a Z_2 gauge field. The Z_2 gauge field part contributes to the
universal "topological entanglement entropy" of the ground state while the
fermion part is responsible for the non-local entanglement carried by the Z_2
vortices (visons) in the non-Abelian phase. Our result also enables the
calculation of the entire entanglement spectrum and the more general Renyi
entropy of the Kitaev model. Based on our results we propose a new quantity to
characterize topologically ordered states--the capacity of entanglement, which
can distinguish the states with and without topologically protected gapless
entanglement spectrum.Comment: 4.0 pages + supplementary material, published version in Phys. Rev.
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