85,219 research outputs found
Detecting the orbital character of the spin fluctuation in the Iron-based superconductors with the resonant inelastic X-ray scattering spectroscopy
The orbital distribution of the spin fluctuation in the iron-based
superconductors(IBSs) is the key information needed to understand the
magnetism, superconductivity and electronic nematicity in these multi-orbital
systems. In this work, we propose that the resonant inelastic X-ray
scattering(RIXS) technique can be used to probe selectively the spin
fluctuation on different Fe orbitals. In particular, the spin fluctuation
on the three orbitals, namely, the , and the
orbital, can be selectively probed in the
scattering geometry by aligning the direction of the outgoing photon in the
, and direction. Such orbital-resolved information on the spin
fluctuation is invaluable for the study of the orbital-selective physics in the
IBSs and can greatly advance our understanding on the relation between orbital
ordering and spin nematicity in the IBSs and the orbital-selective pairing
mechanism in these multi-orbital systems.Comment: 6 pages with new and more informative figures, the explicit form of
the RIXS matrix element is provided, and the discussion part has been
rewritte
Vanishing pseudogap around in an electron-doped high- superconductor: a simple picture
Recent ARPES measurement on electron-doped cuprate
finds
that the pseudogap along the boundary of the antiferromagnetic Brillouin
zone(AFBZ) exhibits dramatic momentum dependence. In particular, the pseudogap
vanishes in a finite region around the anti-nodal point, in which a single
broadened peak emerges at the un-renormalized quasiparticle energy. Such an
observation is argued to be inconsistent with the antiferromagnetic(AFM)
band-folding picture, which predicts a constant pseudogap along the AFBZ
boundary. On the other hand, it is claimed that the experimental results are
consistent with the prediction of the cluster dynamical mean field
theory(CDMFT) simulation on the Hubbard model, in which the pseudogap is
interpreted as a s-wave splitting between the Hubbard bands and the in-gap
states. Here we show that the observed momentum dependence of the pseudogap is
indeed consistent with AFM band-folding picture, provided that we assume the
existence of a strongly momentum dependent quasiparticle scattering rate. More
specifically, we show that the quasiparticle scattering rate acts to reduce the
spectral gap induced by AFM band-folding effect. The new quasiparticle poles
corresponding to the AF-split bands can even be totally eliminated when the
scattering rate exceeds the bare band folding gap, leaving the system with a
single pole at the un-renormalized quasiparticle energy. We predict that the
pseudogap should close in a square root fashion as we move toward
along the AFBZ boundary. Our results illustrates again that the quasiparticle
scattering rate can play a much more profound role than simply broadening the
quasiparticle peak in the quasiparticle dynamics of strongly correlated
electron systems.Comment: 5 pages, 2 figures, new references adde
Proton decay suppression in a supersymmetric SO(10) model
We propose a mechanism for sufficient suppression of dimension-5 operators
for proton decay in a supersymmetric SO(10) model. This mechanism is analogue
to the double seesaw mechanism in studying neutrino masses. Only an
intermediate VEV instead of an intermediate scale is required so that gauge
coupling unification is maintained. The VEV is generated by introducing an
anomalous U(1) symmetry whose breaking is at higher scale. The proton decay
amplitudes are suppressed by this VEV over the GUT scale. We use
in breaking GUT symmetry. is included so that
fermion sector is fully realistic. Assuming a minimal fine-tuning in the Higgs
doublet sector, of order one is predicted.Comment: Several small corrections, 13 pages, no figur
Entanglement in the anisotropic Heisenberg XYZ model with different Dzyaloshinskii-Moriya interaction and inhomogeneous magnetic field
We investigate the entanglement in a two-qubit Heisenberg XYZ system with
different Dzyaloshinskii-Moriya(DM) interaction and inhomogeneous magnetic
field. It is found that the control parameters (, and )
are remarkably different with the common control parameters (,
and ) in the entanglement and the critical temperature, and these
x-component parameters can increase the entanglement and the critical
temperature more efficiently. Furthermore, we show the properties of these
x-component parameters for the control of entanglement. In the ground state,
increasing (spin-orbit coupling parameter) can decrease the critical
value and increase the entanglement in the revival region, and
adjusting some parameters (increasing and , decreasing and
) can decrease the critical value to enlarge the revival
region. In the thermal state, increasing can increase the revival
region and the entanglement in the revival region (for or ), and
enhance the critical value to make the region of high entanglement
larger. Also, the entanglement and the revival region will increase with the
decrease of (uniform magnetic field). In addition, small
(nonuniform magnetic field) has some similar properties to , and with
the increase of the entanglement also has a revival phenomenon, so that
the entanglement can exist at higher temperature for larger .Comment: 8 pages, 8 figure
Towards the fate of natural composite Higgs model through single search at the 8 TeV LHC
We analyze the observational potential of single production in both the
and decay channels at 8 TeV
LHC using an integrated luminosity of 25 . Our analysis is
based on a simplified model with minimal coset in which the
is a singlet of the unbroken SO(4). The single production, as a
consequence of electroweak symmetry breaking, is less kinematically suppressed,
associated with a light forward jet and has boosted decay products at the 8 TeV
LHC. Therefore it provides the most promising channel in searching for a heavy
. We have exploited the above kinematical features and used the jet
substructure method to reconstruct the boosted Higgs in decay channel. It
is shown that a strong constraint on the coupling () at the 95% C. L. can be obtained for GeV.Comment: 22 pages, 8 figures, 5 tables, refs added in v
Probing the CP-even Higgs Sector via in the Natural NMSSM
After the discovery of a Standard Model (SM) like Higgs boson, naturalness
strongly favors the next to the Minimal Supersymmetric SM (NMSSM). In this
letter, we point out that the most natural NMSSM predicts the following CP-even
Higgs sector: (A) is the SM-like Higgs boson with mass
pushed-upward by a lighter with mass overwhelmingly within
; (B) GeV; (C)
has a significant coupling to top quarks and can decay to with a
large branching ratio. Using jet substructure we show that all the three Higgs
bosons can be discovered via at
the 14 TeV LHC. Especially, the LEP-LHC scenario with GeV has a
very good discovery potential.Comment: 5 pages, 2 figures. Some typos corrected and reference adde
Proton decay in a supersymmetric SO(10) model with missing partner mechanism
The extended supersymmetric SO(10) model with missing partner mechanism is
studied. An intermediate vacuum expectation value is incorporated which
corresponds to the see-saw scale. Gauge coupling unification is not broken
explicitly. Proton decay is found to satisfy the present experimental limits at
the cost of fine-tuning some parameters.Comment: 14 pages; Several improvements, References adde
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