Inhomogeneity Effects in Topological Superconductors

We have constructed a quasiclassical framework on superconductors with strong spin-orbit couplings, applicable to CuxBi2Se3[Y. Nagai, H. Nakamura, and M. Machida: arXiv:1305.3025]. The notable point is that in this framework the Bogoliubov-de Gennes Hamiltonians with suggested odd-parity pairing states turn to quasiclassical ones with usual spin-triplet Cooper pairs. Using this quasiclassical theory, we can investigate inhomogeneity effects such as the phenomena with vortices and surfaces in this superconductors and shed light on the pairing state of topological superconductors. In this paper, we apply the quasiclassical framework to the surface bound states with the Dirac-cone energy dispersion originated from the topological invariant in the parent compound Bi2Se3 in order to investigate the robustness of these bound states under the superconducting order parameter. The odd-parity gap functions can not open on the Dirac-cone-dispersion band in the Cu-doped Bi$_{2}$Se$_{3}$ superconductor. We show that the massless Dirac quasiparticles originated from the normal-state topological invariant and the Majorana quasiparticles coexist with each other on the surface in the odd-parity topological superconductivity. Inhomogeneity effects can be easily investigated with the use of our quasiclassical framework in topological superconductors.Comment: 6 pages, 2 figures, submitted to SCES 2013 proceeding

Cis-Cotranscription of Two Beta Globin Genes during Chicken Primitive Hematopoiesis

Chicken beta globin locus contains four genes, two of which, rho and epsilon, are expressed from the earliest stage of primitive hematopoiesis. Here we show that the transcription of these two genes in the nucleus engages in “on/off” phases. During each “on” phase, cotranscription of rho and epsilon in cis is favored. We propose that these two chicken beta globin genes are transcribed not by competing for a transcription initiation complex, but in a cooperative way

Highly Functionalized Lithium-Ion Battery

Future energy demand is an important issue that requires consideration. Lithium-ion batteries (LIB) are one of the most popular types of rechargeable battery for portable electronic devices, such as mobile phones, cameras, and laptop computers, and have led to other applications being commercialized. Distributed power generation using renewable energy sources, such as solar photovoltaic (PV), can efficiently supply electricity according to on-site demand. If the electrodes of a LIB could function as a solar cell, the storage device could provide electricity without an electric power supply

DMFT Reveals the Non-Hermitian Topology and Fermi Arcs in Heavy-Fermion Systems.

When a strongly correlated system supports well-defined quasiparticles, it allows for an elegant one-body effective description within the non-Hermitian topological theory. While the microscopic many-body Hamiltonian of a closed system remains Hermitian, the one-body quasiparticle Hamiltonian is non-Hermitian due to the finite quasiparticle lifetime. We use such a non-Hermitian description in the heavy-fermion two-dimensional systems with the momentum-dependent hybridization to reveal a fascinating phenomenon which can be directly probed by the spectroscopic measurements, the bulk "Fermi arcs." Starting from a simple two-band model, we first combine the phenomenological approach with the perturbation theory to show the existence of the Fermi arcs and reveal their connection to the topological exceptional points, special points in the Brillouin zone where the Hamiltonian is nondiagonalizable. The appearance of such points necessarily requires that the electrons belonging to different orbitals have different lifetimes. This requirement is naturally satisfied in the heavy-fermion systems, where the itinerant c electrons experience much weaker interaction than the localized f electrons. We then utilize the dynamical mean field theory to numerically calculate the spectral function and confirm our findings. We show that the concept of the exceptional points in the non-Hermitian quasiparticle Hamiltonians is a powerful tool for predicting new phenomena in strongly correlated electron systems

Polymerase arrest at the λP_R promoter during transcription initiation

During transcription initiation by Escherichia coli RNA polymerase, a fraction of the homogeneous enzyme population has been kinetically shown to form two types of nonproductive complexes at some promoters: moribund complexes, which produce only abortive transcripts and fully inactive ternary complexes (Kubori, T., and Shimamoto, N. (1996) J. Mol. Biol. 256, 449–457). Here we report biochemical isolation of the complexes arrested at the λPR promoter and an analysis of their structure by DNA and protein footprintings. We found that the isolated promoter-arrested complexes retain a stoichiometric amount of ζ70 subunit. Exonuclease III footprints of the arrested complexes are backtracked compared with that of the binary complex, and KMnO4 footprinting reveals a decrease in the melting of DNA in the promoter region. Protein footprints of the retained ζ70 have shown a more exposed conformation in region 3, compared with binary complexes. This feature is similar to that of the complexes arrested in inactive state during transcription elongation, indicating the existence of a common inactivating mechanism during transcription initiation and elongation. The possible involvement of the promoter arrest in transcriptional regulation is discussed