Sökning: "lattice"

Visar resultat 21 - 25 av 699 avhandlingar innehållade ordet lattice.

  1. 21. Classifications and volume bounds of lattice polytopes

    Författare :Gabriele Balletti; Benjamin Nill; Martin Henk; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : In this licentiate thesis we study relations among invariants of lattice polytopes, with particular focus on bounds for the volume.In the first paper we give an upper bound on the volume vol(P^*) of a polytope P^* dual to a d-dimensional lattice polytope P with exactly one interiorlattice point, in each dimension d. LÄS MER

  3. 22. Linear and Nonlinear Mechanics of Lattice Materials : Computational Modelling and Experiments

    Författare :Danial Molavitabrizi; Mahmoud Mousavi; Kristofer Gamstedt; Haiyang Yu; Samuel Forest; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Teknisk fysik med inriktning mot tillämpad mekanik; Engineering science with specialization in Applied Mechanics;

    Sammanfattning : Lattice materials are artificial materials made of repeating unit-cells. The internal architecture of these materials can be engineered for a specific application such as energy absorption, heat transfer, or acoustic damping. LÄS MER

  4. 23. Two topics in cryptography : lattice problems and the security of protocols

    Författare :Mårten Trolin; Johan Håstad; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Datalogi; Datalogi; Computer science; Datalogi;

    Sammanfattning : In this thesis we present new results in two areas – cryptographic protocols and lattice problems. • We present a new protocol for electronic cash which is designed to function on hardware with limited computing power. The scheme has provable security properties and low computational requirements, but it still gives a fair amount of privacy. LÄS MER

  5. 24. Electron-Lattice Dynamics in pi-Conjugated Systems

    Författare :Magnus Hultell (Andersson); Sven Stafström; Alexander Onipko; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Polaron dynamics; Exciton dynamics; pi-conjugated systems; Su-Schrieffer-Heeger SSH model; Adiabaticity; Charge carrier transport; Organic electronics.; Computational physics; Beräkningsfysik;

    Sammanfattning : In this thesis we explore in particular the dynamics of a special type of quasi-particle in pi-conjugated materials termed polaron, the origin of which is intimately related to the strong interactions between the electronic and the vibrational degrees of freedom within these systems. In order to conduct such studies with the particular focus of each appended paper, we simultaneously solve the time-dependent Schrödinger equation and the lattice equation of motion with a three-dimensional extension of the famous Su-Schrieffer-Heeger (SSH) model Hamiltonian. LÄS MER

  7. 25. Topological band theory and Majorana fermions : With focus on self-consistent lattice models

    Författare :Kristofer Björnson; Annica M. Black-Schaffer; Jonas Fransson; Olle Eriksson; Andrei Bernevig; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Topology; Majorana; superconductivity; material physics; numerical calculations; tight-binding; mean-field;

    Sammanfattning : One of the most central concepts in condensed matter physics is the electronic band structure. Although band theory was established more than 80 years ago, recent developments have led to new insights that are formulated in the framework of topological band theory. LÄS MER