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Results for "Jaroslav Hančl"

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Metrical irrationality results related to values of the Riemann $ζ$-functionFeb 12 2018We introduce a one-parameter family of series associated to the Riemann $\zeta$-function and prove that the values of the elements of this family at integers are linearly independent over the rationals for almost all values of the parameter, where almost ... More
One-sided Diophantine approximationsSep 04 2018Jan 15 2019The paper deals with best one--sided (lower or upper) Diophantine approximations of the $\ell$-th kind ($\ell\in\mathbb{N}$). We use the ordinary continued fraction expansions to formulate explicit criteria for a fraction $\frac{p}{q}\in\mathbb{Q}$ to ... More
On the KK system as two-kaons systemApr 01 2005The time evolution of the KK system as a two-qubit system is given. The effect which is interpreted as CP violation in neutral kaon decays is explained via violation of quantum correlations during time evolution of the KK system as two-kaons system and ... More
Low Ply Drawings of TreesAug 30 2016Sep 02 2016We consider the recently introduced model of \emph{low ply graph drawing}, in which the ply-disks of the vertices do not have many common overlaps, which results in a good distribution of the vertices in the plane. The \emph{ply-disk} of a vertex in a ... More
The generic rank for $A$--plannar structuresJun 18 2012The paper mostly collects material on generic rank of $A$--modules with respect to differential geometric applications. Our research was motivated by geometry of $A$--structures. In particular, we discuss the case where $A$ is an unitary associative algebra ... More
A role of antiquantum bits for superdense coding and quantum computingFeb 03 1999We define an anti-quantum bit state via analogous way as the anti-state in Particle Physics.We show the quantum information Feymann diagrams for the teleportations and superdense coding, which preserve the information flow. The role of information vacuum ... More
Super quantum mechanics, spacetime and quantum informationApr 09 2008In the paper it is shown the connection between spacetime and quantum information using an information spacetime as superspace. The connection of quantum information with anticommuting variables is given . Also a solitonic bag is presented where the information ... More
Q-deformation, discrete time and quantum information as fiber spaceJan 11 2008In this paper we show the connection between the q-deformation and discrete time, starting from the q-deformed Heisenberg uncertainty relation and q-deformation calculus. We show that time has discrete nature and for this case we construct the connection ... More
Supersymmetry and quantum gamesMar 29 2007In this paper we show the connection between the supersymmetry and quantum games.
A role of topology and quantum information in physicsFeb 18 2005The role of topology in QIS with physical connection to the noncommutativity, discretization,supersymmetry, entanglement, nonseparability and CP violation in physics is discussed.
Theoretical Investigation of C_60 IR SpectrumFeb 16 1996Feb 19 1996A semi-empirical model of the infrared (IR) spectrum of the C$_{60}$ molecule is proposed. The weak IR-active modes seen experimentally in a C$_{60}$ crystalline sample are argued to be combination modes caused by anharmonicity. The origin of these 2-mode ... More
Measurement of the Spectra of Single Bubble Sonoluminescence in waterJul 22 2016A preliminary results of measurement of the spectra of Single Bubble Sonoluminescence (SBSL) in water are presented. Analysis concentrates on similarity and differences of spectra from black-body radiation like shape.
Spectral fluctuations of the atomic vibrations in glasses: random matrix theory and beyondApr 24 2001It is demonstrated on a realistic model of amorphous alloy Si$_{0.9}$Ge$_{0.1}$ with 1000 atoms, that short-range spectral fluctuations of propagons and diffusons are universal and in agreement with random matrix theory. The universality ceases at distances ... More
On the Decay of Localized Vibrational States in Glasses: a one-dimensional exampleOct 14 1996The interaction between three localized vibrational modes is shown to be as relevant for the lifetimes of localized modes as the interaction involving two localized and one extended, and one localized and two extended modes. This contrasts with previous ... More
Double-grid quadrature with interpolation-projection (DoGIP) as a novel discretisation approach: An application to FEM on simplexesOct 26 2017Nov 30 2018This paper is focused on the double-grid integration with interpolation-projection (DoGIP), which is a novel discretisation approach of variational formulations. The method, introduced for Fourier--Galerkin method, is described here as a more general ... More
A Bayesian Network Model for Interesting ItemsetsOct 14 2015Mining itemsets that are the most interesting under a statistical model of the underlying data is a frequently used and well-studied technique for exploratory data analysis. The most recent models of interestingness are predominantly based on maximum ... More
Parameter-Free Probabilistic API Mining at GitHub ScaleDec 17 2015Existing API mining algorithms are not yet practical to use as they require expensive parameter tuning and the returned set of API calls can be large, highly redundant and difficult to understand. In an attempt to remedy these shortcomings we present ... More
Raman Tensor Calculation for Magnesium PhthalocyanineNov 08 2005We present ab-initio density functional (DFT) calculations of the vibrational spectra of neutral Magnesium phthalocyanine (MgPc) molecule and of its Raman scattering intensities.
Entanglement distillation by adiabatic passage in coupled quantum dotsDec 09 2004Adiabatic passage of two correlated electrons in three coupled quantum dots is shown to provide a robust and controlled way of distilling, transporting and detecting spin entanglement, as well as of measuring the rate of spin disentanglement. Employing ... More
Spin switch and spin amplifier: magnetic bipolar transistor in the saturation regimeJun 07 2004It is shown that magnetic bipolar transistors (MBT) can amplify currents even in the saturation regime, in which both the emitter-base and collector-base junctions are forward biased. The collector current and the current gain can change sign as they ... More
SIDDHARTA impact on $\bar{K}N$ amplitudes used in in-medium applicationsJan 25 2013We have performed new fits of our chirally motivated coupled--channels model for meson-baryon interactions and discussed the impact of the SIDDHARTA measurement on the $\bar{K}N$ amplitudes in the free space and in nuclear medium. The kaon--nucleon amplitudes ... More
Rich Kozai-Lidov Dynamics in an Initially Thin and Eccentric Stellar Disc Around a Supermassive Black HoleFeb 17 2016There is growing evidence of star formation in the vicinity of supermassive black holes (SMBH) in galactic nuclei. A viable scenario for this process assumes infall of a massive gas cloud towards the SMBH and subsequent formation of a dense accretion ... More
Effect of the toroidal magnetic field on the runaway instability of relativistic toriMay 28 2013Runaway instability operates in fluid tori around black holes. It affects systems close to the critical (cusp overflowing) configuration. The runaway effect depends on the radial profile l(R) of the angular momentum distribution of the fluid, on the dimension-less ... More
Curved planar quantum wires with Dirichlet and Neumann boundary conditionsMar 05 2002Apr 17 2002We investigate the discrete spectrum of the Hamiltonian describing a quantum particle living in the two-dimensional curved strip. We impose the Dirichlet and Neumann boundary conditions on opposite sides of the strip. The existence of the discrete eigenvalue ... More
Local control of a mechanism with the growth vector (4,7)Feb 23 2018We study local control of the mechanism with the growth vector (4,7). We study controllability and optimal control on the nilpotent approximation as an example of the cotrol theory on Lie group. We give solutions of the system an show examples of the ... More
Breakdown of the Hebel-Slichter effect in superconducting graphene due to the emergence of Yu-Shiba-Rusinov states at magnetic resonant scatterersFeb 14 2019We study theoretically the relaxation of electron spins in graphene in proximity to an $s$-wave superconductor in the presence of resonant magnetic and spin-orbit impurities. Off resonance, the relaxation behaves as predicted from superconducting coherence: ... More
Ramsey Partial Orders from Acyclic GraphsAug 16 2016We prove that finite partial orders with a linear extension form a Ramsey class. Our proof is based on the fact that class of acyclic graphs has the Ramsey property and uses the partite construction.
Spin-polarized current amplification and spin injection in magnetic bipolar transistorsNov 19 2003The magnetic bipolar transistor (MBT) is a bipolar junction transistor with an equilibrium and nonequilibrium spin (magnetization) in the emitter, base, or collector. The low-injection theory of spin-polarized transport through MBTs and of a more general ... More
The standard model of spin injectionMar 13 20091 Introduction 2 Simple model of spin injection 3 Spin-polarized transport: concepts and definitions 4 The standard model of spin injection: F/N junction 5 Nonequilibrium resistance and spin bottleneck 6 Transparent and tunnel contacts, conductivity mismatch ... More
On the order of countable graphsApr 18 2004A set of graphs is said to be independent if there is no homomorphism between distinct graphs from the set. We consider the existence problems related to the independent sets of countable graphs. While the maximal size of an independent set of countable ... More
Universal structures with forbidden homomorphismsJul 23 2009Mar 02 2013We relate the existence problem of universal objects to the properties of corresponding enriched categories (lifts or expansions). In particular, extending earlier results, we prove that for every (possibly infinite) regular set F of finite connected ... More
Computer networks new generation in the use of RESNov 25 2014The paper is aimed at analyzing the potential of new information networks to solve the problems of energy management network with the use of renewable energy sources. One of the basic problems of renewable energy sources is their temporal and spatial ... More
H to Zn Ionization Equilibrium for the Non-Maxwellian Electron kappa-distributions: Updated CalculationsApr 15 2013New data for calculation of the ionization and recombination rates have have been published in the past few years. Most of these are included in CHIANTI database. We used these data to calculate collisional ionization and recombination rates for the non-Maxwellian ... More
Stokes problem with a solution dependent slip bound: Stability of solutions with respect to domainsApr 27 2015We study the Stokes problem in a bounded planar domain $\Omega$ with a friction type boundary condition that switches between a slip and no-slip stage. Unlike our previous work [6], in the present paper the threshold value may depend on the velocity field. ... More
Control of electron spin and orbital resonance in quantum dots through spin-orbit interactionsNov 08 2006Aug 09 2007Influence of resonant oscillating electromagnetic field on a single electron in coupled lateral quantum dots in the presence of phonon-induced relaxation and decoherence is investigated. Using symmetry arguments it is shown that spin and orbital resonance ... More
Spin-Voltaic Effect and its ImplicationsApr 22 2003In an inhomogeneously doped magnetic semiconductor, an interplay between an equilibrium magnetization and injected nonequilibrium spin leads to the spin-voltaic effect--a spin analogue of the photo-voltaic effect. By reversing either the sign of the equilibrium ... More
Self-sustained magnetoelectric oscillations in magnetic resonant tunneling structuresMay 27 2008The dynamic interplay of transport, electrostatic, and magnetic effects in the resonant tunneling through ferromagnetic quantum wells is theoretically investigated. It is shown that the carrier-mediated magnetic order in the ferromagnetic region not only ... More
Proposal for a digital converter of analog magnetic signalsOct 23 2006A device which converts analog magnetic signals directly into digital information is proposed. The device concept is based on the monostable-bistable transition logic element, which consists of two resonant tunneling diodes (load and driver) connected ... More
Gravity On-shell DiagramsApr 12 2016We study on-shell diagrams for gravity theories with any number of supersymmetries and find a compact Grassmannian formula in terms of edge variables of the graphs. Unlike in gauge theory where the analogous form involves only $\dlog$-factors, in gravity ... More
Quantification of entanglement by means of convergent iterationsMay 13 2002A convergent iterative procedure is proposed for the calculation of the relative entropy of entanglement of a given bipartite quantum state. When this state turns out to be non-separable the algorithm provides the corresponding optimal entanglement witness ... More
Computing Enclosures of Overdetermined Interval Linear SystemsApr 17 2013This work considers special types of interval linear systems - overdetermined systems. Simply said these systems have more equations than variables. The solution set of an interval linear system is a collection of all solutions of all instances of an ... More
Subsquares Approach - Simple Scheme for Solving Overdetermined Interval Linear SystemsMay 05 2013In this work we present a new simple but efficient scheme - Subsquares approach - for development of algorithms for enclosing the solution set of overdetermined interval linear systems. We are going to show two algorithms based on this scheme and discuss ... More
Splitting finite antichains in the homomorphism orderJan 15 2008Mar 09 2008A structural condition is given for finite maximal antichains in the homomorphism order of relational structures to have the splitting property. It turns out that non-splitting antichains appear only at the bottom of the order. Moreover, we examine looseness ... More
Dynamic modeling of gene expression in prokaryotes: application to glucose-lactose diauxie in Escherichia coliJun 01 2011Coexpression of genes or, more generally, similarity in the expression profiles poses an unsurmountable obstacle to inferring the gene regulatory network (GRN) based solely on data from DNA microarray time series. Clustering of genes with similar expression ... More
Can Google searches help nowcast and forecast unemployment rates in the Visegrad Group countries?Aug 28 2014Online activity of the Internet users has been repeatedly shown to provide a rich information set for various research fields. We focus on the job-related searches on Google and their possible usefulness in the region of the Visegrad Group -- the Czech ... More
Geometry of almost Cliffordian manifolds: classes of subordinated connectionsMay 28 2012An almost Clifford and an almost Cliffordian manifold is a $G$--structure based on the definition of Clifford algebras. An almost Clifford manifold based on $\mathcal O:= \cc l (s,t)$ is given by a reduction of the structure group $GL(km, \mathbb R)$ ... More
Ramsey theorem for designsMay 08 2017We prove that for any choice of parameters $k,t,\lambda$ the class of all finite ordered designs with parameters $k,t,\lambda$ is a Ramsey class.
Ramsey Classes with Closure Operations (Selected Combinatorial Applications)May 04 2017Jun 06 2017We state the Ramsey property of classes of ordered structures with closures and given local properties. This generalises many old and new results: the Ne\v{s}et\v{r}il-R\"{o}dl Theorem, the author's Ramsey lift of bowtie-free graphs as well as the Ramsey ... More
Bound states in straight quantum waveguides with combined boundary conditionsDec 11 2001We investigate the discrete spectrum of the Hamiltonian describing a quantum particle living in the two-dimensional straight strip. We impose the combined Dirichlet and Neumann boundary conditions on different parts of the boundary. Several statements ... More
Optical orientation in bipolar spintronic devicesNov 03 2008Optical orientation is a highly efficient tool for the generation of nonequilibrium spin polarization in semiconductors. Combined with spin-polarized transport it offers new functionalities for conventional electronic devices, such as pn junction bipolar ... More
Resonant Tunneling Magneto Resistance in Coupled Quantum WellsJun 20 2006Jun 21 2006A three barrier resonant tunneling structure in which the two quantum wells are formed by a dilute magnetic semiconductor material (ZnMnSe) with a giant Zeeman splitting of the conduction band is theoretically investigated. Self-consistent numerical simulations ... More
Theory of digital magneto resistance in ferromagnetic resonant tunneling diodesDec 01 2006We propose a ferromagnetic spintronic system, which consists of two serial connected resonant tunneling diodes. One diode is nonmagnetic whereas the other comprises a ferromagnetic emitter and quantum well. Using a selfconsistent coherent transport model ... More
Theory of phonon-induced spin relaxation in laterally coupled quantum dotsDec 29 2005Mar 02 2006Phonon-induced spin relaxation in coupled lateral quantum dots in the presence of spin-orbit coupling is calculated. The calculation for single dots is consistent with experiment. Spin relaxation in double dots at useful interdot couplings is dominated ... More
On the origin and movement of the poles in the coupled channels model for $\bar{K}N$ interactionsJan 25 2013The origin of the poles generated by chiral coupled-channel dynamics and applied to $\bar{K}N$ interactions is related to the nonzero diagonal couplings in the $\pi\Sigma$, $\bar{K}N$ and $K\Xi$ channels. An evolution of the poles from the zero coupling ... More
The properties of hypervelocity stars and S-stars originating from an eccentric disc around a supermassive black holeJun 29 2016Hypervelocity stars (HVSs) that are observed in the Galactic halo, are believed to be accelerated to large velocities by a process of tidal disruption of binary stars passing close to a supermassive black hole (SMBH) which resides in the center of the ... More
Two-body relaxation driven evolution of the young stellar disc in the Galactic CentreApr 01 2014The centre of our Galaxy hosts almost two hundreds of very young stars, a subset of which is orbiting the central supermassive black hole (SMBH) in a relatively thin disc-like structure. First analyses indicated a power-law surface density profile of ... More
Homomorphism and embedding universal structures for restricted classesSep 27 2009Jun 10 2014This paper unifies problems and results related to (embedding) universal and homomorphism universal structures. On the one side we give a new combinatorial proof of the existence of universal objects for homomorphism defined classes of structures (thus ... More
Searching of New Emission-Line Stars using the Astroinformatics ApproachDec 13 2011Using data mining techniques applied on emission line characteristics of Be stars spectra we attempted to find new Be stars candidates in SDSS SEGUE survey. The mid-resolution spectra of confirmed Be stars obtained from VO-compatible archive of Ond\v{r}ejov ... More
Magnetotransport signatures of the proximity exchange and spin-orbit couplings in grapheneAug 12 2016Graphene on an insulating ferromagnetic substrate---ferromagnetic insulator or ferromagnetic metal with a tunnel barrier---is expected to exhibit giant proximity exchange and spin-orbit couplings. We use a realistic transport model of charge-disorder ... More
Bowtie-free graphs have a Ramsey liftFeb 12 2014Oct 11 2016A bowtie is a graph consisting of two triangles with one vertex identified. We show that the class of all (countable) graphs not containing a bowtie as a subgraph have a Ramsey lift (expansion). This solves one of the old problems in the area and it is ... More
Some examples of universal and generic partial ordersFeb 08 2010Jun 18 2010We survey structures endowed with natural partial orderings and prove their universality. These partial orders include partial orders on sets of words, partial orders formed by geometric objects, grammars, polynomials and homomorphism order for various ... More
All those Ramsey classes (Ramsey classes with closures and forbidden homomorphisms)Jun 25 2016Oct 20 2016We prove the Ramsey property of classes of ordered structures with closures and given local properties. This generalises earlier results: the Ne\v{s}et\v{r}il-R\"odl Theorem, the Ramsey property of partial orders and metric spaces as well as the author's ... More
NP by means of lifts and shadowsJun 23 2007We show that every NP problem is polynomially equivalent to a simple combinatorial problem: the membership problem for a special class of digraphs. These classes are defined by means of shadows (projections) and by finitely many forbidden colored (lifted) ... More
All those Ramsey classes (Ramsey classes with closures and forbidden homomorphisms)Jun 25 2016We prove the Ramsey property of classes of ordered structures with closures and given local properties. This generalises earlier results: the Ne\v{s}et\v{r}il-R\"odl Theorem, the Ramsey property of partial orders and metric spaces as well as the author's ... More
Generalized planar curves and quaternionic geometryDec 27 2005Motivated by the analogies between the projective and the almost quaternionic geometries, we study the generalized planar curves and mappings. We follow, recover, and extend the classical approach as developed by Mikes and Sinyukov. Then we exploit the ... More
Orbital and spin relaxation in single and coupled quantum dotsApr 27 2006Phonon-induced orbital and spin relaxation rates of single electron states in lateral single and double quantum dots are obtained numerically for realistic materials parameters. The rates are calculated as a function of magnetic field and interdot coupling, ... More
Spin properties of single electron states in coupled quantum dotsJun 23 2005Spin properties of single electron states in laterally coupled quantum dots in the presence of a perpendicular magnetic field are studied by exact numerical diagonalization. Dresselhaus (linear and cubic) and Bychkov-Rashba spin-orbit couplings are included ... More
First-principles studies of orbital and spin-orbit properties of GaAs, GaSb, InAs, and InSb zinc-blende and wurtzite semiconductorsJun 02 2016We employ first-principles techniques tailored to properly describe semiconductors (modified Becke-Johnson potential added to the exchange-correlation functional), to obtain the electronic band structures of both the zinc-blende and wurtzite phases of ... More
Graphene on transition-metal dichalcogenides: a platform for proximity spin-orbit physics and optospintronicsJun 30 2015Hybrids of graphene and two dimensional transition metal dichalcogenides (TMDC) have the potential to bring graphene spintronics to the next level. As we show here by performing first-principles calculations of graphene on monolayer MoS$_2$, there are ... More
On tension-continuous mapingsFeb 24 2006Tension-continuous (shortly TT) mappings are mappings between the edge sets of graphs. They generalize graph homomorphisms. From another perspective, tension-continuous mappings are dual to the notion of flow-continuous mappings and the context of nowhere-zero ... More
Tension continuous maps--their structure and applicationsMar 17 2005We consider mappings between edge sets of graphs that lift tensions to tensions. Such mappings are called tension-continuous mappings (shortly TT mappings). Existence of a TT mapping induces a (quasi)order on the class of graphs, which seems to be an ... More
Forbidden lists (NP and CSP for combinatorialists)Jun 12 2007We present a definition of the class NP in combinatorial context as the set of languages of structures defined by finitely many forbidden lifted substructures. We apply this to special syntactically defined subclasses and show how they correspond to naturally ... More
Acoustic decoherence of flux qubitsDec 11 2006Decoherence of a flux qubit due to inelastic scattering of thermal phonons by the qubit is studied. The computed decoherence rates contain no unknown constants and are expressed entirely in terms of measurable parameters of the qubit. The answer depends ... More
Thermal Expansion and Gruneisen Parameters of Amorphous Silicon: A Realistic Model CalculationAug 07 1997Using a realistic model, the mode Gruneisen parameters and the temperature dependent coefficient of linear thermal expansion are calculated for amorphous silicon. The resulting values of the Gruneisen parameters differ from the crystalline case in having ... More
Beam test of the QMB6 calibration board and HBU0 prototypeMay 24 2011We report about the performance of the HBU0 board and the optical calibration system QMB6 in the DESY test beam. A MIP signal was measured on the HBU0 board, providing a reference to the LED amplitude scan, showing an amount of light delivered to each ... More
Into the AmplituhedronDec 30 2013We initiate an exploration of the physics and geometry of the amplituhedron, starting with the simplest case of the integrand for four-particle scattering in planar N=4 SYM. We show how the textbook structure of the unitarity double-cut follows from the ... More
Ignition of superconducting vortices by acoustic standing wavesSep 11 2007Nov 22 2007Nucleation of vortices in a superconductor below the first critical field can be assisted by transverse sound in the GHz frequency range. Vortices will enter and exist the superconductor at the frequency of the sound. We compute the threshold parameters ... More
Anharmonic Decay of Vibrational States in Amorphous SiliconMay 16 1996Anharmonic decay rates are calculated for a realistic atomic model of amorphous silicon. The results show that the vibrational states decay on picosecond timescales and follow the two-mode density of states, similar to crystalline silicon, but somewhat ... More
Electric fields with ultrasoft pseudo-potentials: applications to benzene and anthraceneMar 11 2004We present density functional perturbation theory for electric field perturbations and ultra-soft pseudopotentials. Applications to benzene and anthracene molecules and surfaces are reported as examples. We point out several issues concerning the evaluation ... More
The AmplituhedronDec 06 2013Perturbative scattering amplitudes in gauge theories have remarkable simplicity and hidden infinite dimensional symmetries that are completely obscured in the conventional formulation of field theory using Feynman diagrams. This suggests the existence ... More
Anisotropic tunneling magnetoresistance and tunneling anisotropic magnetoresistance: spin-orbit coupling in magnetic tunnel junctionsJul 22 2008The effects of the spin-orbit interaction on the tunneling magnetoresistance of ferromagnet/semiconductor/normal metal tunnel junctions are investigated. Analytical expressions for the tunneling anisotropic magnetoresistance (TAMR) are derived within ... More
Phonon-induced spin relaxation of conduction electrons in aluminumApr 09 1999Spin-flip Eliashberg function $\alpha_S^2F$ and temperature-dependent spin relaxation time $T_1(T)$ are calculated for aluminum using realistic pseudopotentials. The spin-flip electron-phonon coupling constant $\lambda_S$ is found to be $2.5\times 10^{-5}$. ... More
Voltage from mechanical stress in type-II superconductors: Depinning of the magnetic flux by moving dislocationsFeb 27 2008Jul 02 2008Mechanical stress causes motion of defects in solids. We show that in a type-II superconductor a moving dislocation generates a pattern of current that exerts the depinning force on the surrounding vortex lattice. Concentration of dislocations and the ... More
Theory of sound attenuation in glasses: The role of thermal vibrationsJan 08 1999Sound attenuation and internal friction coefficients are calculated for a realistic model of amorphous silicon. It is found that, contrary to previous views, thermal vibrations can induce sound attenuation at ultrasonic and hypersonic frequencies that ... More
Accurate computation of conditional expectation for highly non-linear problemsJun 08 2018Jan 31 2019This paper focuses on inverse problems to identify parameters by incorporating information from measurements. These generally ill-posed problems are formulated here in a probabilistic setting based on Bayes's theorem because it leads to a unique solution ... More
Towards a classification for quasiperiodically forced circle homeomorphismsFeb 07 2005Poincare's classification of the dynamics of homeomorphisms of the circle is one of the earliest, but still one of the most elegant, classification results in dynamical systems. Here we generalize this to quasiperiodically forced circle homeomorphisms, ... More
Spin transport in inhomogeneous magnetic fields: a proposal for Stern-Gerlach-like experiments with conduction electronsApr 09 2001Jun 06 2002Spin dynamics in spatially inhomogeneous magnetic fields is studied within the framework of Boltzmann theory. Stern-Gerlach-like separation of spin up and spin down electrons occurs in ballistic and diffusive regimes, before spin relaxation sets in. Transient ... More
Spin relaxation of conduction electronsJan 18 1999Prospect of building electronic devices in which electron spins store and transport information has revived interest in the spin relaxation of conduction electrons. Since spin-polarized currents cannot flow indefinitely, basic spin-electronic devices ... More
Local Integrand Representations of All Two-Loop Amplitudes in Planar SYMMay 21 2015We use generalized unitarity at the integrand-level to directly construct local, manifestly dual-conformally invariant formulae for all two-loop scattering amplitudes in planar, maximally supersymmetric Yang-Mills theory (SYM). This representation separates ... More
How well can you know the edge of a quantum pyramid?May 04 2009We consider a symmetric quantum communication scenario in which the signal states are edges of a quantum pyramid of arbitrary dimension and arbitrary shape, and all edge states are transmitted with the same probability. The receiver could employ different ... More
Proposal for a ferromagnetic multiwell spin oscillatorMay 12 2010The highly nonlinear coupling of transport and magnetic properties in a multiwell heterostructure, which comprises ferromagnetic quantum wells made of diluted magnetic semiconductors, is theoretically investigated. The interplay of resonant tunneling ... More
Spin-polarized bipolar transport and its applicationsJun 27 2002In spin-polarized bipolar transport both electrons and holes in doped semiconductors contribute to spin-charge coupling. The current conversion between the minority (as referred to carriers and not spin) and majority carriers leads to novel spintronic ... More
Theory of spin-polarized bipolar transport in magnetic p-n junctionsMay 16 2002The interplay between spin and charge transport in electrically and magnetically inhomogeneous semiconductor systems is investigated theoretically. In particular, the theory of spin-polarized bipolar transport in magnetic p-n junctions is formulated, ... More
Spin injection through the depletion layer: a theory of spin-polarized p-n junctions and solar cellsMar 22 2001A drift-diffusion model for spin-charge transport in spin-polarized {\it p-n} junctions is developed and solved numerically for a realistic set of material parameters based on GaAs. It is demonstrated that spin polarization can be injected through the ... More
Spin-orbit coupling and anisotropic exchange in two-electron double quantum dotsApr 15 2010Jul 22 2010The influence of the spin-orbit interactions on the energy spectrum of two-electron laterally coupled quantum dots is investigated. The effective Hamiltonian for a spin qubit pair proposed in F. Baruffa et al., Phys. Rev. Lett. 104, 126401 (2010) is confronted ... More
Cluster Analysis of Local Convergent Sequences of StructuresOct 27 2015The cluster analysis of very large objects is an important problem, which spans several theoretical as well as applied branches of mathematics and computer science. Here we suggest a novel approach: under assumption of local convergence of a sequence ... More
The coupling of a young stellar disc with the molecular torus in the Galactic centreNov 16 2010The Galactic centre hosts, according to observations, a number of early-type stars. About one half of those which are orbiting the central supermassive black hole on orbits with projected radii $\gtrsim$ 0.03 pc form a coherently rotating disc. Observations ... More
Informationally Incomplete Quantum TomographySep 11 2013Nov 13 2013In quantum-state tomography on sources with quantum degrees of freedom of large Hilbert spaces, inference of quantum states of light for instance, a complete characterization of the quantum states for these sources is often not feasible owing to limited ... More
Theory of spin-polarized transport in semiconductor heterojunctions: Proposal for spin injection and detection in siliconDec 21 2004Dec 22 2004Spin injection and detection in silicon is a difficult problem, in part because the weak spin-orbit coupling and indirect gap preclude using standard optical techniques. We propose two ways to overcome this difficulty, and illustrate their operation by ... More
Power convergence of Abel averagesAug 04 2012Necessary and sufficient conditions are presented for the Abel averages of discrete and strongly continuous semigroups, $T^k$ and $T_t$, to be power convergent in the operator norm in a complex Banach space. These results cover also the case where $T$ ... More