7,896 research outputs found
Topological invariants for holographic semimetals
We study the behavior of fermion spectral functions for the holographic
topological Weyl and nodal line semimetals. We calculate the topological
invariants from the Green functions of both holographic semimetals using the
topological Hamiltonian method, which calculates topological invariants of
strongly interacting systems from an effective Hamiltonian system with the same
topological structure. Nontrivial topological invariants for both systems have
been obtained and the presence of nontrivial topological invariants further
supports the topological nature of the holographic semimetals.Comment: 39 pages, 11 figures, 1 table; v2: match published versio
Topological nodal line semimetals in holography
We show a holographic model of a strongly coupled topological nodal line
semimetal (NLSM) and find that the NLSM phase could go through a quantum phase
transition to a topologically trivial state. The dual fermion spectral function
shows that there are multiple Fermi surfaces each of which is a closed nodal
loop in the NLSM phase. The topological structure in the bulk is induced by the
IR interplay between the dual mass operator and the operator that deforms the
topology of the Fermi surface. We propose a practical framework for building
various strongly coupled topological semimetals in holography, which indicates
that at strong coupling topologically nontrivial semimetal states generally
exist.Comment: 21 pages, 5 figures; v2: match published versio
Constraints on large-extra-dimensions model through 125 GeV Higgs pair production at the LHC
Based on the analysis of 5 fb^-1 of data at the LHC, the ATLAS and CMS
collaborations have presented evidence for a Higgs boson with a mass in the 125
GeV range. We consider the 125 GeV neutral Higgs pair production process in the
context of large-extra-dimensions (LED) model including the Kaluza-Klein
(KK)excited gravitons at the LHC. We consider the standard model(SM) Higgs pair
production in gluon-gluon fusion channel and pure LED effects through graviton
exchange as well as their interferences. It is shown that such interferences
should be included; the LED model raises the transverse momentum (Pt)and
invariant mass (M_HH) distributions at high scales of Pt and M_HH of the Higgs
pair production. By using the Higgs pair production we could set the discovery
limit on the cutoff scale M_S up to 6 TeV for delta = 2 and 4.5 TeV for delta =
6.Comment: 6 figure
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