Cycle of the needs satisfaction, and information support of the society development simulation system

The report focuses on some of the key points of constructing a model of an artificial society. It is based on the processes of emergence and implementation of the needs of specific agents, depending on the internal processes in the agents, and external environmental factors. Unlike in other approaches, the basis of the modeled system agents' behavior is the concept of needs as the necessity of implementation of the agents' transition from one state to another. This article presents an algorithm of the needs satisfaction of the agent, starting with the event that caused the need for, and ending its satisfaction, or the message that it is impossible to satisfy. The basis of objective knowledge in the system are a model of active and passive agents, as well as recipes meet the needs of the active agents and the relationships between them. © 2017 Author(s)

Spin wave dispersion based on the quasiparticle self-consistent GWGW method: NiO, MnO and α\alpha-MnAs

We present spin wave dispersions in MnO, NiO, and $\alpha$-MnAs based on the quasiparticle self-consistent $GW$ method (\qsgw), which determines an optimum quasiparticle picture. For MnO and NiO, \qsgw results are in rather good agreement with experiments, in contrast to the LDA and LDA+U description. For $\alpha$-MnAs, we find a collinear ferromagnetic ground state in \qsgw, while this phase is unstable in the LDA.Comment: V2: add another figure for SW life time. Formalism is detaile

Superconducting and Normal State Properties of Neutron Irradiated MgB2

We have performed a systematic study of the evolution of the superconducting and normal state properties of neutron irradiated MgB$_2$ wire segments as a function of fluence and post exposure annealing temperature and time. All fluences used suppressed the transition temperature, Tc, below 5 K and expanded the unit cell. For each annealing temperature Tc recovers with annealing time and the upper critical field, Hc2(T=0), approximately scales with Tc. By judicious choice of fluence, annealing temperature and time, the Tc of damaged MgB2 can be tuned to virtually any value between 5 and 39 K. For higher annealing temperatures and longer annealing times the recovery of Tc tends to coincide with a decrease in the normal state resistivity and a systematic recovery of the lattice parameters.Comment: Updated version, to appear in Phys. Rev.

The recursive algorithm in the model of agents’ needs implementation

The paper is devoted to the development of model construction principles of an artificial society development. This model is based on the actualization and implementation of specific agents’ needs. The "engine" of the model is the dynamic actualization of agents’ needs considering constant tendency of agents to strengthening and/or preservation of the opportunities including their movement in space. In the absence of conditions for implementation of the chosen need satisfaction recipe, secondary needs are recursively generated and thus the agent’s behavior strategy is defined.Данная работа посвящена разработке принципов построения модели развития искусственного общества, основанной на процессах возникновения и реализации потребностей конкретных агентов. «Движком» модели является динамическая актуализация потребностей агентов, учитывающая постоянное стремление агентов к усилению и\или сохранению своих возможностей, в том числе с учетом их перемещения в пространстве. При отсутствии условий для выполнения выбранного рецепта удовлетворения потребности рекурсивно генерируются другие потребности, и таким образом определяется стратегия поведения агента

Phenomenological Model of Longitudinal Spin Fluctuations in Itinerant Antiferromagnets

We present the phenomenological analysis of the spectrum of longitudinal spin fluctuations in isotropic itinerant electron antiferromagnets with account of spin anharmonicity giving rise to coupling of transverse and longitudinal normal modes. The spectrum consists of a quasielastic part forming a central peak or a dip, depending on temperature and the Landau relaxation rate. Effects of spin fluctuation coupling also give rise to an inelastic part of the spectrum which has a form of resonances or antiresonances near the magnon frequencies related to non-propagating longitudinal excitations

Magnetic susceptibility, exchange interactions and spin-wave spectra in the local spin density approximation

Starting from exact expression for the dynamical spin susceptibility in the time-dependent density functional theory a controversial issue about exchange interaction parameters and spin-wave excitation spectra of itinerant electron ferromagnets is reconsidered. It is shown that the original expressions for exchange integrals based on the magnetic force theorem (J. Phys. F14 L125 (1984)) are optimal for the calculations of the magnon spectrum whereas static response function is better described by the ``renormalized'' magnetic force theorem by P. Bruno (Phys. Rev. Lett. 90, 087205 (2003)). This conclusion is confirmed by the {\it ab initio} calculations for Fe and Ni.Comment: 12 pages, 2 figures, submitted to JPC

Electron-phonon interaction in ultrasmall-radius carbon nanotubes

We perform analysis of the band structure, phonon dispersion, and electron-phonon interactions in three types of small-radius carbon nanotubes. We find that the (5,5) can be described well by the zone-folding method and the electron-phonon interaction is too small to support either a charge-density wave or superconductivity at realistic temperatures. For ultra-small (5,0) and (6,0) nanotubes we find that the large curvature makes these tubes metallic with a large density of states at the Fermi energy and leads to unusual electron-phonon interactions, with the dominant coupling coming from the out-of-plane phonon modes. By combining the frozen-phonon approximation with the RPA analysis of the giant Kohn anomaly in 1d we find parameters of the effective Fr\"{o}lich Hamiltonian for the conduction electrons. Neglecting Coulomb interactions, we find that the (5,5) CNT remains stable to instabilities of the Fermi surface down to very low temperatures while for the (5,0) and (6,0) CNTs a CDW instability will occur. When we include a realistic model of Coulomb interaction we find that the charge-density wave remains dominant in the (6,0) CNT with $T_{\rm CDW}$ around 5 K while the charge-density wave instability is suppressed to very low temperatures in the (5,0) CNT, making superconductivity dominant with transition temperature around one Kelvin.Comment: 20 pages. Updated 7/23/0