Bogolyubov Institute for Theoretical Physics
of the National Academy of Sciences of Ukraine

Department of Quantum Electronics
  • The Hamiltonian and Poisson structures of integrable nonlinear Schrödinger system on a triangular-lattice ribbon have been found in the case of attractive nonlinearity.
    O.O. Vakhnenko
  • A coupling between chiralities in spin and physical spaces has been found. The mechanism of the coupling is elucidated by using the Möbious ring as a case study. Due to the topology of the Möbious ring its ground state is a vortex state.
    V.P. Kravchuk, Yu.B. Gaididei
  • The one-electron spectrum, eigenstates and Green functions of bounded graphene nanoribbons that describe electron dynamics have been found. On this basis, we obtained the analytic expressions for transmission coefficients for different carbon nanostructures. The obtained results have numerous applications to the construction of multi-terminal graphene-based electronic devices.
    L.I. Malysheva
  • The mechanism of DNA deactivation under the irradiation of biological organisms by high energy ion beams has been introduced. Within the framework of this mechanism it is considered the formation of stable complexes of molecular products of water radiolysis (hydrogen peroxide) with the active centers of recognition of DNA double helix (РО4 groups). The calculations of the complex energy show that DNA phosphate groups and counterions can form stable complexes with hydrogen peroxide molecules, which are as stable as the complexes with water molecules. The interaction of H2O2 molecule with phosphate group of the double helix backbone can disrupt DNA biological function and induce the deactivation of the cell genetic apparatus.
    D.V. Piatnytskyi, O.O. Zdorevskyi, S.M. Perepelytsya, S.N. Volkov
  • The method of stabilization of the fluctuations of an optical free-space channel by means of beam expansion was proposed and experimentally studied. It was shown that if the fluctuations in the channel are concerned with the atmospheric effects which result in the beam wandering around the aperture, then the beam expansion allows one to stabilize the transmittance fluctuations at the same time reducing the mean transmittance. The realization of quantum communication through a stabilized channel was modelled theoretically and it was shown that for the given channel and other parameters there exists an optimal regime of fluctuation stabilization which enables the maximally effective communication.
    V. Usenko
  • We develop a general theory of magnetization dynamics of curvilinear low-dimensional ferromagnetic systems: one-dimensional nanowires and two-dimensional shells of an arbitrary form. It is shown that the curvature of the magnet leads to additional terms in the exchange energy, namely effective anisotropy and Dzyaloshinskii-like interactions.
    Yu.B. Gaididei, V.P. Kravchuk
  • Explicit expressions for the Green functions of armchair carbon nanotubes and zigzag graphene nanoribbons are obtained in the form suitable for direct applications. The obtained results are based on the analytic solution to the Schrodinger equation for the tight-binding Hamiltonian of bounded armchair nanotubes and zigzag nanoribbons. The Green functions can be used for the analysis of electronic structures and transport properties of carbon nanotubes and graphene.
    L. Malysheva
  • The mechanism of threshold deformation of the polymorphic macromolecule is proposed and the interpretation of DNA double helix overstretching effect is given. It is shown that the polymorphic macromolecule has an additional (to usual elastic) mechanisms of deformation which induced by intrinsic conformational transformations. Under the critical value of acting force the deformation becomes the threshold character due to the formation of bistable conformational state and dynamics of the stretched domains in macromolecule chain.
    S.N. Volkov
  • The possibility of an arbitrary number of vortex-antivortex pairs generation in vortex-state magnetic nanodisk is demonstrated. The mentioned generation occurs under influence of the external magnetic field of the certain space and time configuration. Scheme of an experimental setup for observation of the mentioned phenomena is proposed. The theoretical model is build, the model is based on the nonlinear resonance in system of certain magnon modes. Theoretical results are verified using micromagnetic modeling.
    Yu. Gaididei, V.P. Kravchuk, D.D. Sheka