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 $\tan\beta$ 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$_{2}$ 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$_{2}$ spin liquid turns out to be $d + i d'$ singlet pairing, but time reversal symmetry is preserved, taking $d + i d'$ in one valley and $d - i d'$ 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$_{2}$ spin liquid are shown to be continuous while the transition from the Z$_{2}$ spin liquid to the antiferromagnetic Mott insulator turns out to be the first order. We emphasize that both algebraic spin liquid and $d \pm id'$ Z$_{2}$ 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$_{2}$ 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 $N$, $\Sigma$, $\Xi$, $\Delta$, $\Sigma^*$, and $\Xi^*$ 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 $\pi$-dressing and spontaneous chiral-symmetry breaking is discussed