Entangled Electronic States in Multiple Quantum-Dot Systems

We present an analytically solvable model of $P$ colinear, two-dimensional quantum dots, each containing two electrons. Inter-dot coupling via the electron-electron interaction gives rise to sets of entangled ground states. These ground states have crystal-like inter-plane correlations and arise discontinously with increasing magnetic field. Their ranges and stabilities are found to depend on dot size ratios, and to increase with $P$.Comment: To appear in Physical Review B (in press). RevTeX file. Figures available from [email protected]

Non-equilibrium Kondo effect in asymmetrically coupled quantum dot

The quantum dot asymmetrically coupled to the external leads has been analysed theoretically by means of the equation of motion (EOM) technique and the non-crossing approximation (NCA). The system has been described by the single impurity Anderson model. To calculate the conductance across the device the non-equilibrium Green's function technique has been used. The obtained results show the importance of the asymmetry of the coupling for the appearance of the Kondo peak at nonzero voltages and qualitatively explain recent experiments.Comment: 7 pages, 6 figures, Physical Review B (accepted for publication

Renormalization approach for quantum-dot structures under strong alternating fields

We develop a renormalization method for calculating the electronic structure of single and double quantum dots under intense ac fields. The nanostructures are emulated by lattice models with a clear continuum limit of the effective-mass and single-particle approximations. The coupling to the ac field is treated non-perturbatively by means of the Floquet Hamiltonian. The renormalization approach allows the study of dressed states of the nanoscopic system with realistic geometries as well arbitrary strong ac fields. We give examples of a single quantum dot, emphasizing the analysis of the effective-mass limit for lattice models, and double-dot structures, where we discuss the limit of the well used two-level approximation.Comment: 6 pages, 7 figure

Tannerella serpentiformis sp. nov., isolated from the human mouth

Three strains representing the previously uncultured human oral Tannerella taxon HMT-286 were recently isolated from the subgingival plaque of a patient with chronic periodontitis. The phenotypic and genetic features of strain SP18_26T were compared to those of the type species of Tannerella , Tannerella forsythia . A genome size of 2.97 Mbp (G+C content 56.5 mol%) was previously reported for SP18_26T, compared to a size of 3.28 Mbp (47.1 mol%) in T. forsythia ATCC 43037T. 16S rRNA gene sequence comparisons also revealed 94.3 % sequence identity with T. forsythia ATCC 43037T. Growth was stimulated by supplementation of media with N-acetyl muramic acid, as seen with T. forsythia , but the cells displayed a distinctive snake-like morphology. Fatty acid methyl ester analysis revealed a profile differing from T. forsythia , chiefly in the amount of 3-OH-16 : 0 (four-fold lower in SP18_26T). Overall, metabolic enzyme activity also differed from T. forsythia , with enzyme activity for indole present, but the complement of glycoside hydrolase enzyme activity was smaller than T. forsythia , for example, lacking sialidase and N-acetyl-β-glucosaminidase – evidence backed up by analysis of its gene content. On the basis of these results, a new species Tannerella serpentiformis is proposed for which the type strain is SP18_26T (=DSM 102894T=JCM 31303T)