Thermal activation energy of 3D vortex matter in NaFe1-xCoxAs (x=0.01, 0.03 and 0.07) single crystals

We report on the thermally activated flux flow dependency on the doping dependent mixed state in NaFe1-xCoxAs (x=0.01, 0.03, and 0.07) crystals using the magnetoresistivity in the case of B//c-axis and B//ab-plane. It was found clearly that irrespective of the doping ratio, magnetoresistivity showed a distinct tail just above the Tc, offset associated with the thermally activated flux flow (TAFF) in our crystals. Furthermore, in TAFF region the temperature dependence of the activation energy follows the relation U(T, B)=U_0 (B) (1-T/T_c )^q with q=1.5 in all studied crystals. The magnetic field dependence of the activation energy follows a power law of U_0 (B)~B^(-{\alpha}) where the exponent {\alpha} is changed from a low value to a high value at a crossover field of B=~2T, indicating the transition from collective to plastic pinning in the crystals. Finally, it is suggested that the 3D vortex phase is the dominant phase in the low-temperature region as compared to the TAFF region in our series samples

Land use survey and mapping and water resources investigation in Korea

The author has identified the following significant results. Land use imagery is applicable to land use classification for small scale land use mapping less than 1:250,000. Land use mapping by satellite is more efficient and more cost-effective than land use mapping from conventional medium altitude aerial photographs. Six categories of level 1 land use classification are recognizable from MSS imagery. A hydrogeomorphological study of the Han River basin indicates that band 7 is useful for recognizing the soil and the weathering part of bed rock. The morphological change of the main river is accurately recognized and the drainage system in the area observed is easily classified because of the more or less simple rock type. Although the direct hydrological characteristics are not obtained from the MSS imagery, the indirect information such as the permeability of the soil and the vegetation cover, is helpful in interpreting the hydrological aspects

Sudden death of effective entanglement

Sudden death of entanglement is a well-known effect resulting from the finite volume of separable states. We study the case when the observer has a limited measurement capability and analyse the effective entanglement, i.e. entanglement minimized over the output data. We show that in the well defined system of two quantum dots monitored by single electron transistors, one may observe a sudden death of effective entanglement when real, physical entanglement is still alive. For certain measurement setups, this occurs even for initial states for which sudden death of physical entanglement is not possible at all. The principles of the analysis may be applied to other analogous scenarios, such as etimation of the parameters arising from quantum process tomography.Comment: final version, 5 pages, 3 figure

Partial scaling transform of multiqubit states as a criterion of separability

The partial scaling transform of the density matrix for multiqubit states is introduced to detect entanglement of quantum states. The transform contains partial transposition as a special case. The scaling transform corresponds to partial time scaling of subsystem (or partial Planck's constant scaling) which was used to formulate recently separability criterion for continous variables.A measure of entanglement which is a generalization of negativity measure is introduced being based on tomographic probability description of spin states.Comment: 16 pages, 5 figures, submitted to J. Phys. A: Math. Ge

Angle Dependence of Landau Level Spectrum in Twisted Bilayer Graphene

In the context of the low energy effective theory, the exact Landau level spectrum of quasiparticles in twisted bilayer graphene with small twist angle is analytically obtained by spheroidal eigenvalues. We analyze the dependence of the Landau levels on the twist angle to find the points, where the two-fold degeneracy for twist angles is lifted in the nonzero modes and below/above which massive/massless fermion pictures become valid. In the perpendicular magnetic field of 10\,T, the degeneracy is removed at $\theta_{{\rm deg}}\sim 3^\circ$ %angles around 3 degrees for a few low levels, specifically, $\theta_{\rm deg}\simeq 2.56^\circ$ for the first pair of nonzero levels and $\theta_{\rm deg}\simeq 3.50^\circ$ for the next pair. Massive quasiparticle appears at $\theta<\theta_{{\rm c}}\simeq 1.17^\circ$ in 10\,T, %angles less than 1.17 degrees. which match perfectly with the recent experimental results. Since our analysis is applicable to the cases of arbitrary constant magnetic fields, we make predictions for the same experiment performed in arbitrary constant magnetic fields, e.g., for B=40\,T we get $\theta_{\rm c}\simeq 2.34^\circ$ and the sequence of angles $\theta_{\rm deg} = 5.11, 7.01, 8.42,...$ for the pairs of nonzero energy levels. The symmetry restoration mechanism behind the massive/massless transition is conjectured to be a tunneling (instanton) in momentum space.Comment: 8 pages, 7 figures, version to appear in PR

Temperature-dependent Fermi surface evolution in heavy fermion CeIrIn5

In Cerium-based heavy electron materials, the 4f electron's magnetic moments bind to the itinerant quasiparticles to form composite heavy quasiparticles at low temperature. The volume of the Fermi surfacein the Brillouin zone incorporates the moments to produce a "large FS" due to the Luttinger theorem. When the 4f electrons are localized free moments, a "small FS" is induced since it contains only broad bands of conduction spd electrons. We have addressed theoretically the evolution of the heavy fermion FS as a function of temperature, using a first principles dynamical mean-field theory (DMFT) approach combined with density functional theory (DFT+DMFT). We focus on the archetypical heavy electrons in CeIrIn5, which is believed to be near a quantum critical point. Upon cooling, both the quantum oscillation frequencies and cyclotron masses show logarithmic scaling behavior (~ ln(T_0/T)) with different characteristic temperatures T_0 = 130 and 50 K, respectively. The resistivity coherence peak observed at T ~ 50 K is the result of the competition between the binding of incoherent 4f electrons to the spd conduction electrons at Fermi level and the formation of coherent 4f electrons.Comment: 5 pages main article,3 figures for the main article, 2 page Supplementary information, 2 figures for the Supplementary information. Supplementary movie 1 and 2 are provided on the webpage(http://www-ph.postech.ac.kr/~win/supple.html

iNID: An Analytical Framework for Identifying Network Models for Interplays among Developmental Signaling in Arabidopsis

Integration of internal and external cues into developmental programs is indispensable for growth and development of plants, which involve complex interplays among signaling pathways activated by the internal and external factors (IEFs). However, decoding these complex interplays is still challenging. Here, we present a web-based platform that identifies key regulators and Network models delineating Interplays among Developmental signaling (iNID) in Arabidopsis. iNID provides a comprehensive resource of (1) transcriptomes previously collected under the conditions treated with a broad spectrum of IEFs and (2) protein and genetic interactome data in Arabidopsis. In addition, iNID provides an array of tools for identifying key regulators and network models related to interplays among IEFs using transcriptome and interactome data. To demonstrate the utility of iNID, we investigated the interplays of (1) phytohormones and light and (2) phytohormones and biotic stresses. The results revealed 34 potential regulators of the interplays, some of which have not been reported in association with the interplays, and also network models that delineate the involvement of the 34 regulators in the interplays, providing novel insights into the interplays collectively defined by phytohormones, light, and biotic stresses. We then experimentally verified that BME3 and TEM1, among the selected regulators, are involved in the auxin-brassinosteroid (BR)-blue light interplay. Therefore, iNID serves as a useful tool to provide a basis for understanding interplays among IEFs.X115Ysciescopu