14,628 research outputs found
Real space renormalization of Majorana fermions in quantum nano-wire superconductors
We have applied the real space quantum renormalization group approach to
study the topological quantum phase transition in the one-dimensional chain of
a spinless p-wave superconductor. We investigate the behavior of local
compressibility and ground-state fidelity of the Kitaev chain. We show that the
topological phase transition is signaled by the maximum of local
compressibility at the quantum critical point tuned by the chemical potential.
Moreover, a sudden drop of the ground-state fidelity and the divergence of
fidelity susceptibility at the topological quantum critical point have been
used as a proper indicators for the topological quantum phase transition, which
signals the appearance of Majorana fermions. We also present the scaling
analysis of ground-state fidelity near the critical point that manifests the
universal information about the topological phase transition.Comment: 7 pages, 9 figures; to appear in Journal of the Physical Society of
Japan (JPSJ
Lepton flavour violation in the supersymmetric type-II seesaw mechanism
We summarize the predictions for the radiative decays l_j->l_i \gamma within
the context of the supersymmetric type II seesaw mechanism considering
universal boundary conditions for the soft SUSY breaking terms. The dependence
on the low-energy neutrino parameters is discussed and the deviations from the
analytical results for large analyzed.Comment: 3 pages, 4 figures. To appear in the proceedings of 16th
International Conference on Supersymmetry and the Unification of Fundamental
Interactions (SUSY08), Seoul, Korea, 16-21 Jun 200
Spin liquids in graphene
We reveal that local interactions in graphene allow novel spin liquids
between the semi-metal and antiferromagnetic Mott insulating phases, identified
with algebraic spin liquid and Z spin liquid, respectively. We argue that
the algebraic spin liquid can be regarded as the two dimensional realization of
one dimensional spin dynamics, where antiferromagnetic correlations show
exactly the same power-law dependence as valence bond correlations. Nature of
the Z spin liquid turns out to be singlet pairing, but time
reversal symmetry is preserved, taking in one valley and
in the other valley. We propose the quantized thermal valley Hall effect as an
essential feature of this gapped spin liquid state. Quantum phase transitions
among the semi-metal, algebraic spin liquid, and Z spin liquid are shown
to be continuous while the transition from the Z spin liquid to the
antiferromagnetic Mott insulator turns out to be the first order. We emphasize
that both algebraic spin liquid and Z spin liquid can be
verified by the quantum Monte Carlo simulation, showing the enhanced symmetry
in the algebraic spin liquid and the quantized thermal valley Hall effect in
the Z spin liquid
Vertex correction and Ward identity in the U(1) gauge theory with Fermi surface
We show that introduction of vertex corrections in the fully self-consistent
ladder approximation does not modify dynamics of spinons and gauge fluctuations
in the U(1) gauge theory with Fermi surface
Biological evaluations of novel 2,3,3-Trisphosphonate in osteoclastic and osteoblastic activities
Bisphosphonates (BPs) are the first line treatment for many bone diseases including hypercalcimia associated with bone malignancies. In this paper, we introduce a new analogue of bisphosphonate called the 2,3,3-Trisphosphonate (2,3,3-TriPP) that was synthesised in a two steps reaction. In vitro investigations using a medically known bisphosphonate (Etidronate) and the 2,3,3-TrisPP were performed with an aim to evaluate biological effect of this novel compound in major bone cells. 2,3,3-TrisPP showed to have potential to supress the bone resorption process, as our data found that this novel compound exhibited cytotoxic effect in osteoclastic cells at a low concentration of 0.172 mg/mL (LC50). A molecular docking computational simulation calculated a high level of binding affinity between the human farnesyl pyrophosphate synthase (hFPPS) and 2,3,3-TrisPP. This calculation suggested 2,3,3TrisPP may have undergone the mevalonate pathway to prevent the prenylation step during biosynthesis and subsequently resulted in the deactivation of osteoclastic cells. Finally, high levels of osteoblast mineralisation potentials were recorded upon treatments with 2,3,3-TrisPP (0.01-0.1 mg/ml), which implied 2,3,3-TrsiPP may also facilitate bone regeneration.Peer reviewe
Axial charges of octet and decuplet baryons
We present a study of axial charges of baryon ground and resonant states with
relativistic constituent quark models. In particular, the axial charges of
octet and decuplet , , , , , and
baryons are considered. The theoretical predictions are compared to existing
experimental data and results from other approaches, notably from lattice
quantum chromodynamics and chiral perturbation theory. The relevance of axial
charges with regard to -dressing and spontaneous chiral-symmetry breaking
is discussed
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