Results for "Rok Žitko"
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Cesium bright matter-wave solitons and soliton trainsFeb 08 2019Mar 05 2019A study of bright matter-wave solitons of a cesium Bose-Einstein condensate (BEC) is presented. Production of a single soliton is demonstrated and dependence of soliton atom number on the interatomic interaction is investigated. Formation of soliton trains ... More Nanostructured and Modulated Low-Dimensional SystemsMar 26 2013Charge density wave (CDW) ordering in NbSe3 and the structurally related quasi one-dimensional compounds is reconsidered. Since the modulated ground state is characterized by unstable nano-domains, the structural information obtained from diffraction ... More Superconducting quantum dot and the sub-gap statesJan 04 2019Quantum dots are nanostructures made of semiconducting materials that are engineered to hold a small amount of electric charge (a few electrons) that is controlled by external gate and may hence be considered as tunable artificial atoms. A quantum dot ... More Outerstring graphs are $χ$-boundedDec 05 2013Dec 02 2018An outerstring graph is an intersection graph of curves that lie in a common half-plane and have one endpoint on the boundary of that half-plane. We prove that the class of outerstring graphs is $\chi$-bounded, which means that their chromatic number ... More Cesium bright matter-wave solitons and soliton trainsFeb 08 2019A setup for studying bright matter-wave solitons of a cesium Bose-Einstein condensate (BEC) is presented. Production of a single soliton is demonstrated and dependence of soliton atom number on the interatomic interaction is studied. Formation of soliton ... More Outerstring graphs are $χ$-boundedDec 05 2013Feb 03 2016An outerstring graph is an intersection graph of curves lying in a halfplane with one endpoint on the boundary of the halfplane. It is proved that the outerstring graphs are $\chi$-bounded, that is, their chromatic number is bounded by a function of their ... More Enhanced Conductance Through Side-Coupled Double Quantum DotsOct 20 2005Conductance, on-site and inter-site charge fluctuations and spin correlations in the system of two side-coupled quantum dots are calculated using the Wilson's numerical renormalization group (NRG) technique. We also show spectral density calculated using ... More Anomaly in the heat capacity of Kondo superconductorsNov 09 2008Nov 12 2008Using numerical renormalization group we study thermodynamic properties of a magnetic impurity described by the Anderson impurity model in a superconducting host material described by the BCS Hamiltonian. When the Kondo temperature in the normal state, ... More Quantum impurity coupled to Majorana edge fermionsAug 31 2011Oct 20 2011We study a quantum impurity coupled to the edge states of a two-dimensional helical topological superconductor, i.e., to a pair of counterpropagating Majorana fermion edge channels with opposite spin polarizations. For an impurity described by the Anderson ... More Link prediction in Foursquare networkFeb 11 2016Foursquare is an online social network and can be represented with a bipartite network of users and venues. A user-venue pair is connected if a user has checked-in at that venue. In the case of Foursquare, network analysis techniques can be used to enhance ... More Coloring curves that cross a fixed curveDec 18 2015Aug 04 2016We prove that for every integer $t\geq 1$, the class of intersection graphs of curves in the plane each of which crosses a fixed curve in at least one and at most $t$ points is $\chi$-bounded. As a corollary, we prove that for any integers $k\geq 2$ and ... More Coloring curves that cross a fixed curveDec 18 2015Oct 04 2017We prove that for every integer $t\geq 1$, the class of intersection graphs of curves in the plane each of which crosses a fixed curve in at least one and at most $t$ points is $\chi$-bounded. This is essentially the strongest $\chi$-boundedness result ... More Ground state of the parallel double quantum dot systemNov 18 2011We resolve the controversy regarding the ground state of the parallel double quantum dot system near half filling. The numerical renormalization group (NRG) predicts an underscreened Kondo state with residual spin-1/2 magnetic moment, ln 2 residual impurity ... More Conflict-Free Coloring of String GraphsDec 12 2017Jan 18 2019Conflict-free coloring (in short, CF-coloring) of a graph $G = (V,E)$ is a coloring of $V$ such that the neighborhood of each vertex contains a vertex whose color differs from the color of any other vertex in that neighborhood. Bounds on CF-chromatic ... More Vibrational Andreev bound states in magnetic moleculesMay 09 2012We predict the existence of vibrational Andreev bound states in deformable magnetic molecules on superconducting surfaces. We discuss the Anderson impurity model with electron-phonon coupling to a realistic anharmonic vibrational mode that modulates the ... More Superconductivity in the Kondo lattice modelAug 28 2009We study the Kondo lattice model with additional attractive interaction between the conduction electrons within the dynamical mean-field theory using the numerical renormalization group to solve the effective quantum impurity problem. In addition to normal-state ... More Prioritizing network communitiesMay 07 2018May 28 2018Uncovering modular structure in networks is fundamental for systems in biology, physics, and engineering. Community detection identifies candidate modules as hypotheses, which then need to be validated through experiments, such as mutagenesis in a biological ... More Magnetic impurities in spin-split superconductorsNov 25 2016Hybrid semiconductor-superconductor quantum dot devices are tunable physical realizations of quantum impurity models for a magnetic impurity in a superconducting host. The binding energy of the localized sub-gap Shiba states is set by the gate voltages ... More Quantum impurity on the surface of a topological insulatorMar 29 2010Feb 04 2011It is shown that the Hamiltonian for a quantum magnetic impurity on the surface of a topological insulator can be mapped to the conventional pseudo-gap Anderson impurity model, albeit with the combinations of continuum states which hybridize with the ... More Spin thermopower in the overscreened Kondo modelJul 08 2013We study the spin thermopower in the two-channel spin-1/2 Kondo model which exhibits the phenomenon of impurity spin overscreening and non-Fermi-liquid properties. While magnetic field lower than the Kondo temperature does not strongly polarize the impurity ... More Cyclic colorings of plane graphs with independent facesNov 17 2008Let G be a plane graph with maximum face size D. If all faces of G with size four or more are vertex disjoint, then G has a cyclic coloring with D+1 colors, i.e., a coloring such that all vertices incident with the same face receive distinct colors. MASA: Motif-Aware State Assignment in Noisy Time Series DataSep 06 2018Jun 23 2019Complex systems, such as airplanes, cars, or financial markets, produce multivariate time series data consisting of a large number of system measurements over a period of time. Such data can be interpreted as a sequence of states, where each state represents ... More Historical observations of STEVEJul 23 2018Recent work by MacDonald et al. has highlighted the valuable work carried out by sky watchers and auroral enthusiasts in obtaining high-quality digital images of rare and unusual auroral structures. A feature of particular interest, which has been nicknamed ... More Magnetic impurities in spin-split superconductorsNov 25 2016Feb 15 2017Hybrid semiconductor-superconductor quantum dot devices are tunable physical realizations of quantum impurity models for a magnetic impurity in a superconducting host. The binding energy of the localized sub-gap Shiba states is set by the gate voltages ... More Spin-thermopower in interacting quantum dotsSep 14 2011Feb 16 2012Using analytical arguments and the numerical renormalization group method we investigate the spin-thermopower of a quantum dot in a magnetic field. In the particle-hole symmetric situation the temperature difference applied across the dot drives a pure ... More Two-Impurity Yu-Shiba-Rusinov States in Coupled Quantum DotsDec 21 2018Using Coulomb blockaded double quantum dots, we realize the superconducting analog of the celebrated two-impurity Kondo model. Focusing on gate regions with a single spin-1/2 on each dot, we demonstrate gate-tuned changes of the ground state from an interdot ... More Supercurrent in a double quantum dotAug 17 2018Oct 15 2018We demonstrate the Josephson effect in a serial double quantum dot defined in a nanowire with epitaxial superconducting leads. The supercurrent stability diagram adopts a honeycomb pattern with electron-hole and left-right reflection symmetry. We observe ... More Hydrogenation Properties of the TiBx StructuresJul 30 2011Titanium borates show promissing hydrogen storage characteristics. Structural relaxation around individual hydrogen atoms and the binding energies are studied by means of the density functional theory methods for a number of hydrogenated TiB2, TiB and ... More The Impact of Stellar Migration on Disk OutskirtsJun 06 2017Stellar migration, whether due to trapping by transient spirals (churning), or to scattering by non-axisymmetric perturbations, has been proposed to explain the presence of stars in outer disks. After a review of the basic theory, we present compelling, ... More SnapVX: A Network-Based Convex Optimization SolverSep 21 2015SnapVX is a high-performance Python solver for convex optimization problems defined on networks. For these problems, it provides a fast and scalable solution with guaranteed global convergence. SnapVX combines the capabilities of two open source software ... More Correlation Effects in Side-Coupled Quantum DotsMay 31 2007Using Wilson's numerical renormalization group (NRG) technique we compute zero-bias conductance and various correlation functions of a double quantum dot (DQD) system. We present different regimes within a phase diagram of the DQD system. By introducing ... More Clues to Radial Migration from the Properties of Outer DisksJul 12 2008Jul 30 2008The outer disks of galaxies present a unique laboratory for studying the process of disk formation. A considerable fraction of observed disks exhibit a break in their surface brightness profiles. The ubiquity of these features points to a crucial aspect ... More Beyond Inside-Out Growth: Formation and Evolution of Disk OutskirtsOct 29 2007Feb 25 2008We have performed a high mass and force resolution simulation of an idealized galaxy forming from dissipational collapse of gas embedded in a spherical dark matter halo. The simulation includes star formation and effects of stellar feedback. In our simulation ... More Monotonicity of Fitness Landscapes and Mutation Rate ControlSep 04 2012The typical view in evolutionary biology is that mutation rates are minimised. Contrary to that view, studies in combinatorial optimisation and search have shown a clear advantage of using variable mutation rates as a control parameter to optimise the ... More