Momentum-resolved tunneling between Luttinger liquids

We study tunneling between two nearby cleaved edge quantum wires in a perpendicular magnetic field. Due to Coulomb forces between electrons, the wires form a strongly-interacting pair of Luttinger liquids. We calculate the low-temperature differential tunneling conductance, in which singular features map out the dispersion relations of the fractionalized quasiparticles of the system. The velocities of several such spin-charge separated excitations can be explicitly observed. Moreover, the proposed measurement directly demonstrates the splintering of the tunneling electrons into a multi-particle continuum of these quasiparticles, carrying separately charge from spin. A variety of corrections to the simple Luttinger model are also discussed.Comment: 4 pages, 5 figures (1 in color

Evaluation of four different strategies to characterize plasma membrane proteins from banana roots

Plasma membrane proteins constitute a very important class of proteins. They are involved in the transmission of external signals to the interior of the cell and selective transport of water, nutrients and ions across the plasma membrane. However, the study of plasma membrane proteins is challenging because of their poor solubility in aqueous media and low relative abundance. In this work, we evaluated four different strategies for the characterization of plasma membrane proteins from banana roots: (i) the aqueous-polymer two-phase system technique (ATPS) coupled to gelelectrophoresis (gel-based), and (ii) ATPS coupled to LC-MS/MS (gel free), (iii) a microsomal fraction and (iv) a full proteome, both coupled to LC-MS/ MS. Our results show that the gel-based strategy is useful for protein visualization but has major limitations in terms of time reproducibility and efficiency. From the gel-free strategies, the microsomal-based strategy allowed the highest number of plasma membrane proteins to be identified, followed by the full proteome strategy and by the ATPS based strategy. The high yield of plasma membrane proteins provided by the microsomal fraction can be explained by the enrichment of membrane proteins in this fraction and the high throughput of the gel-free approach combined with the usage of a fast high-resolution mass spectrometer for the identification of proteins

Characterizing fruit ripening in plantain and Cavendish bananas: A proteomics approach

The fruit physiology of banana cultivars other than Cavendish is poorly understood. To study the ripening process, samples were taken daily from plantain and Cavendish bananas and the ripening stages were determined. We present data from the green to the fully mature stage. By analyzing the protein abundances during ripening we provide some new insights into the ripening process and how plantains fruits are different. Multivariate analysis of the proteins was performed correlated to the starch dynamics. A drop in sucrose synthase and a rise of acid invertase during ripening indicated a change in the balance of the sucrose fate. During ripening, sugars may no longer be available for respiration since they are stored in the vacuoles, making citrate the preferred respiratory substrate. We found significant cultivar specific differences in granule-bound starch synthase, alpha- and beta amylases and cell wall invertase when comparing the protein content at the same ripening stage. This corroborates the difference in starch content/structure between both banana types. Differences in small heat shock proteins and in the cell wall-modifying enzyme xyloglucan endotransglucosylase/hydrolase support respectively the presumed higher carotenoid content and the firmer fruit structure of plantains

Cross-Over between universality classes in a magnetically disordered metallic wire

In this article we present numerical results of conduction in a disordered quasi-1D wire in the possible presence of magnetic impurities. Our analysis leads us to the study of universal properties in different conduction regimes such as the localized and metallic ones. In particular, we analyse the cross-over between universality classes occurring when the strength of magnetic disorder is increased. For this purpose, we use a numerical Landauer approach, and derive the scattering matrix of the wire from electron's Green's function.Comment: Final version, accepted for publication in New Journ. of Physics, 27 pages, 28 figures. Replaces the earlier shorter preprint arXiv:0910.427

Renormalization of modular invariant Coulomb gas and Sine-Gordon theories, and quantum Hall flow diagram

Using the renormalisation group (RG) we study two dimensional electromagnetic coulomb gas and extended Sine-Gordon theories invariant under the modular group SL(2,Z). The flow diagram is established from the scaling equations, and we derive the critical behaviour at the various transition points of the diagram. Following proposal for a SL(2,Z) duality between different quantum Hall fluids, we discuss the analogy between this flow and the global quantum Hall phase diagram.Comment: 10 pages, 1 EPS figure include

Measuring overlaps in mesoscopic spin glasses via conductance fluctuations

We consider the electonic transport in a mesoscopic metallic spin glasses. We show that the distribution of overlaps between spin configurations can be inferred from the reduction of the conductance fluctuations by the magnetic impurities. Using this property, we propose new experimental protocols to probe spin glasses directly through their overlaps

Continuous atom laser with Bose-Einstein condensates involving three-body interactions

We demonstrate, through numerical simulations, the emission of a coherent continuous matter wave of constant amplitude from a Bose-Einstein Condensate in a shallow optical dipole trap. The process is achieved by spatial control of the variations of the scattering length along the trapping axis, including elastic three body interactions due to dipole interactions. In our approach, the outcoupling mechanism are atomic interactions and thus, the trap remains unaltered. We calculate analytically the parameters for the experimental implementation of this CW atom laser.Comment: 11 pages, 4 figure

Current facilitation by plasmon resonances between parallel wires of finite length

The current voltage (IV) characteristics for perpendicular transport through two sequentially coupled wires of finite length is calculated analytically. The transport within a Coulomb blockade step is assisted by plasmon resonances that appear as steps in the IV characteristics with positions and heights depending on inter- and intrawire interactions. In particular, due to the interwire interactions, the peak positions shift to lower voltages in comparison to the noninteracting wires which reflects the facilitation of current by interactions. The interwire interactions are also found to enhance the thermally activated current.Comment: 5 pages, 1figur