Acta Polytechnica. 2013, vol. 53, no. 3
Now showing items 112 of 12

NonHermitian Starshaped Quantum Graphs
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2013)A compact review is given, and a few new numerical results are added to the recent studies of the qpointed onedimensional starshaped quantum graphs. These graphs are assumed endowedwith certain specific, manifestly ... 
Intervals in Generalized Effect Algebras and their Subgeneralized Effect Algebras
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2013)We consider subsets G of a generalized effect algebra E with 0∈G and such that every interval [0, q]G = [0, q]E ∩ G of G (q ∈ G , q ≠ 0) is a subeffect algebra of the effect algebra [0, q]E. We give a condition on E and ... 
Inherited Properties of Effect Algebras Preserved by Isomorphisms
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2013)We show that isomorphism of effect algebras preserves properties of effect algebras derived from effect algebraic sum ? of elements. These are partial order, order convergence, order topology, existence of states and other ... 
Spectral Singularities do not Correspond to Bound States in the Continuum
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2013)We show that, contrary to a claim made in arXiv:1011.0645, the von NeumannWinger bound states that lie in the continuum of the scattering states are fundamentally different from Naimark’s spectral singularities. 
Emmy Noether and Linear Evolution Equations
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2013)Noether’s Theorem relates the Action Integral of a Lagrangian with symmetries which leave it invariant and the first integrals consequent upon the variational principle and the existence of the symmetries. These each have ... 
Stationary and Dynamical Solutions of the GrossPitaevskii Equation for a BoseEinstein Condensate in a PT symmetric Double Well
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2013)We investigate the GrossPitaevskii equation for a BoseEinstein condensate in a PT symmetric doublewell potential by means of the timedependent variational principle and numerically exact solutions. A onedimensional ... 
Spectral Analysis of Schrödinger Operators with Unusual Semiclassical Behavior
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2013)In this paper we discuss several examples of Schrödinger operators describing a particle confined to a region with thin cuspshaped ‘channels’, given either by a potential or by a Dirichlet boundary; we focus on cases when ... 
Weakly Ordered ACommutative Partial Groups of Linear Operators Densely Defined on Hilbert Space
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2013)The notion of a generalized effect algebra is presented as a generalization of effect algebra for an algebraic description of the structure of the set of all positive linear operators densely defined on a Hilbert space ... 
The Twodimensional Harmonic Oscillator on a Noncommutative Space with Minimal Uncertainties
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2013)The two dimensional set of canonical relations giving rise to minimal uncertainties previously constructed from a qdeformed oscillator algebra is further investigated. We provide a representation for this algebra in terms ... 
Complex Covariance
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2013)According to some generalized correspondence principle the classical limit of a nonHermitian quantum theory describing quantum degrees of freedom is expected to be the well known classical mechanics of classical degrees ... 
Generalized Continuity Equation for QuasiHermitian Hamiltonians
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2013)The continuity relation is generalized to quasiHermitian onedimensional Hamiltonians. As an application we show that the reflection and transmission coefficients computed with the generalized current obey the conventional ... 
On the Solvability of Some Partial Differential Inequality
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2013)The Dulac criterion is a classical method for ruling out the existence of periodic solutions in planar differential equations. In this paper the applicability and therefore reversibility of this criterionis under consideration.