Kitaev spin models from topological nanowire networks

We show that networks of topological nanowires can realize the physics of exactly solvable Kitaev spin models with two-body interactions. This connection arises from the description of the low-energy theory of both systems in terms of a tight-binding model of Majorana modes. In Kitaev spin models the Majorana description provides a convenient representation to solve the model, whereas in an array of topological nanowires it arises, because the physical Majorana modes localized at wire ends permit tunnelling between wire ends and across different Josephson junctions. We explicitly show that an array of junctions of three wires -- a setup relevant to topological quantum computing with nanowires -- can realize the Yao-Kivelson model, a variant of Kitaev spin models on a decorated honeycomb lattice. Translating the results from the latter, we show that the network can be constructed to give rise to collective states characterized by Chern numbers \nu = 0, +/-1 and +/-2, and that defects in an array can be associated with vortex-like quasi-particle excitations. Finally, we analyze the stability of the collective states as well as that of the network as a quantum information processor. We show that decoherence inducing instabilities, be them due to disorder or phase fluctuations, can be understood in terms of proliferation of the vortex-like quasi-particles.Comment: 15 pages, 9 figure

Tuning the scattering length on the ground triplet state of Cs_2

We develop two schemes for tuning the scattering length on the ground triplet state of Cs_2. First, an absolute value of the triplet scattering length of ^{133}Cs_2 is determined using the experimental data (Fioretti et al, Eur.Phys.J. 5, 389 (1999)). We demonstrate that the large scattering length can be made small and positive by coupling of the ^3\Sigma_u^+ (6S + 6S) potential to the ^3\Pi_g state by strong off-resonant radiation. A weaker laser field coupling the ^3\Sigma_u^+ (6S + 6S) continuum to the lowest bound level of the excited ^3\Sigma_g^+ (6S + 6P) also leads to a small positive scattering length. In addition, the scattering length of the ^{135}Cs isotope is found to be positive. The method used solves the Schroedinger equation for two electronic states coupled by an electromagnetic field with approximations employed. The scattering length is determined from calculated continuum wavefunctions of low energy.Comment: 4 figures, a discussion of influence of the C_6 coeficient on the scattering length of different isotopes is adde

Kitapçılığımıza dair

Taha Toros Arşivi, Dosya No:111-Kütüphaneler. Not: Gazetenin "Akşamdan Akşama" köşesinde yayımlanmıştır.İstanbul Kalkınma Ajansı (TR10/14/YEN/0033) İstanbul Development Agency (TR10/14/YEN/0033

Model of the Positioning Pneumatic System

Tato práce se zabývá řídicím systémem pro pneumatický obvod. Řídicí jednotka je multifunkční I/O karta MF 634 od firmy Humusoft, která je založena na 32 bitové architektuře. Je připojena k elektronické jednotce, která spojuje prvky polohovacího pneumatického systému. Tato elektronická jednotka je navržena také pro připojení PLC automatu Siemens Simatic S7 1500. Hlavním cílem této práce je sestavit pneumatický obvod, navrhnout polohovací systém a ověřit funkčnost celého obvodu. Dále je cílem identifikovat regulovanou soustavu (pneumatický válec) a provést syntézu regulačního obvodu. Poté navrhnout řídicí algoritmus a ověřit jeho funkčnost.This thesis deal with the control system designed for controlling the pneumatic circuit. The control unit is represented by the I/O card MF 634, made by the company Humusoft, which is based on 32bit architecture. The control unit is connected to the electronic unit, which allows the control system to be connected with other parts of pneumatic circuit. This unit is designed with connector to connect other control system which is PLC controller Siemens Simatic S7 1500. The main goal of this thesis is to build the pneumatic circuit, to design the positioning system and to verify that the whole system is working properly. The next goal is to identify the regulated system and let the synthesis be done. In this thesis the pneumatic circuit was built and was verified that the whole circuit is working properly. The next goal is to design the control algorithm and to verify if it works properly.352 - Katedra automatizační techniky a řízenívýborn

Parametric Geometry Sketch Tool

Cílem této Bakalářské práce je vytvoření návrhu a implementace parametrického geometrického náčrtníku. Práce rovněľ obsahuje vymezení základních pojmů z oblasti dynamické geometrie. Shrnutí současného stavu, popis dnes existujících nástrojů následované vyhodnocením některých jejich vlastnosti. V závěru jsou shrnuty dosaľené výsledky a je navrľeno moľné pokračování v práci.Purpose of this Bachelor's thesis is the design and implementation of Parametric geometry sketch tool. This thesis also includes basic terms of dynamic geometry. Summary of the state of the art, description of existing tools, followed by evaluation of their features. Results and possibilites of future expansion are summarized in the last chapter.

Energy recovery of waste

První část této práce shrnuje problémy vyplývající z nadměrné produkce odpadů a porovnává různé způsoby a technologie jeho zneškodnění. Druhá část práce se zaměřuje na jednu z těchto možností a to spalování odpadů s následným využitím energie. Jsou zde probrána specifika a možnosti této technologie a následně je popsán její stav v České republice.The first part of this thesis sums up problems arising from waste production and compares different ways and technologies of waste treatment. Second part of this thesis focuses on one of these ways, on the incineration of waste with energy recovery. It discusses specifics and possibilities of this technology and describe current situation in the Czech Republic.

Parametric Geometry 3D Sketch Tool

Cílem této práce je seznámení se s 3D parametrickými konstrukčními nástroji a jejich podporou dynamické geometrie. Práce obsahuje vymezení základních pojmů z oblasti parametrické konstrukce v souvislosti s dynamickou geometrií, shrnutí současného stavu, přehled vybraných aplikací tohoto druhu, vyhodnocení jejich vlastností a návrh knihovny pro 3D parametrickou konstrukci v rámci počítačové grafiky s následným návrhem a implementací dané knihovny a testovací aplikace ukazující její použití.Purpose of this thesis is to introduce reader to 3D parametric construction tools and their application with dynamic geometry. Project introduces basic concepts of parametric construction in computer geometry, summary of the state of the art, description of selected parametric geometry software, evaluation of its features and design of 3D parametric geometry library for use in computer graphics followed by implementation of said library and user interface application for evaluation.

50 yıl sonra Tevfik Fikret

Taha Toros Arşivi, Dosya No: 98/A-Tevfik Fikretİstanbul Kalkınma Ajansı (TR10/14/YEN/0033) İstanbul Development Agency (TR10/14/YEN/0033)Ne dramı:Papaz Haluk'un babası olmak!Tevfik Fikret'in Abdülhamid'e karşı tutumu:Önce öğmek sonra söğme