Cyclotron radiation and emission in graphene

Peculiarity in the cyclotron radiation and emission in graphene is theoretically examined in terms of the optical conductivity and relaxation rates to propose that graphene in magnetic fields can be a candidate to realize the Landau level laser, proposed decades ago [H. Aoki, Appl. Phys. Lett. {\bf 48}, 559 (1986)].Comment: 4 pages, 3 figure

U(1) symmetry breaking in one-dimensional Mott insulator studied by the Density Matrix Renormalization Group method

A new type of external fields violating the particle number preservation is studied in one-dimensional strongly correlated systems by the Density Matrix Renormalization Group method. Due to the U(1) symmetry breaking, the ground state has fluctuation of the total particle number, which implies injection of electrons and holes from out of the chain. This charge fluctuation can be relevant even at half-filling because the particle-hole symmetry is preserved with the finite effective field. In addition, we discuss a quantum phase transition obtained by considering the symmetry-breaking fields as a mean field of interchain-hopping.Comment: 7 pages, 4 figure

Electron transport through Aharonov-Bohm interferometer with laterally coupled double quantum dots

We theoretically investigate electron transport through an Aharonov-Bohm interferometer containing laterally coupled double quantum dots. We introduce the indirect coupling parameter $\alpha$, which characterizes the strength of the coupling via the reservoirs between two quantum dots. $|\alpha|=1$ indicates the strongest coupling, where only a single mode contributes to the transport in the system. Two conduction modes exist in a system where $|\alpha|\neq 1$. The interference effects such as the Fano resonance and the Aharonov-Bohm oscillation are suppressed as the absolute value of the parameter $\alpha$ decreases from 1. The linear conductance does not depend on the flux when $\alpha=0$ since it corresponds to independent coupling of the dots to the reservoir modes.Comment: 15 pages, 13 figure

Exotic baryons from a heavy meson and a nucleon - Positive parity states -

We study heavy baryons with exotic flavor quantum numbers formed by a heavy meson and a nucleon (DbarN and BN) with positive parity. One pion exchange interaction, providing a tensor force, dominates as a long range force to bind the DbarN and BN ystems. In the heavy quark mass limit, pseudoscalar meson and vector meson are degenerate and the binding mechanism by the tensor force analogous to that in the nuclear systems becomes important. As a result, we obtain the DbarN and BN resonant states in the J^P=1/2^+, 3/2^+ and 5/2^+ channels with I=0

Topological quantum phase transition in the BEC-BCS crossover phenomena

A crossover between the Bose Einstein condensation (BEC) and BCS superconducting state is described topologically in the chiral symmetric fermion system with attractive interaction. Using a local Z_2 Berry phase, we found a quantum phase transition between the BEC and BCS phases without accompanying the bulk gap closing.Comment: 4 pages, 5 figure

Log-aesthetic Curves as Similarity Geometric Analogue of Euler's Elasticae

In this paper we consider the log-aesthetic curves and their generalization which are used in CAGD. We consider those curves under similarity geometry and characterize them as stationary integrable flow on plane curves which is governed by the Burgers equation. We propose a variational formulation of those curves whose Euler-Lagrange equation yields the stationary Burgers equation. Our result suggests that the log-aesthetic curves and their generalization can be regarded as the similarity geometric analogue of Euler's elasticae

Fermentation Quality of Phasey Bean and Guineagrass Silages

Silages were made from guineagrass (Panicum maximum Jacq. var. maximum) and phasey bean (Macroptilium lathyroides (L.) Urb.) at three-growth stages. The silages were investigated in relation fermentation quality. Phasey bean silage showed a better fermentation quality than guineagrass silage. The latic acid to total acid ratio of phasey bean silage was higher than 500g/kg DM, and the volatile basic nitrogen to total nitrogen ratio was lower than 100g/kg. It is concluded that phasey bean is an unique legume suitable for good silage fermentation