Lattice study of trapped fermions at unitarity

We present a lattice study of up to N=20 unitary fermions confined to a harmonic trap. Our preliminary results show better than 1% agreement with high precision solutions to the many-body Schrodinger equation for up to N=6. We are able to make predictions for larger N which were inaccessible by the Hamiltonian approach due to computational limitations. Harmonic traps are used experimentally to study cold atoms tuned to a Feshbach resonance. We show that they also provide certain benefits to numerical studies of many-body correlators on the lattice. In particular, we anticipate that the methods described here could be used for studying nuclear physics.Comment: 7 pages, 5 figures, presented at the XXVIII International Symposium on Lattice Field Theory (Lattice 2010), Villasimius, Italy, June 14-19 201

Lattice calculation for unitary fermions in a finite box

A fundamental constant in systems of unitary fermions is the so-called Bertsch parameter, the ratio of the ground state energy for spin paired unitary fermions to that for free fermions at the same density. I discuss how we computed this parameter as well as the pairing gap using a recently developed lattice construction for unitary fermions, by measuring correlation functions for up to 38 fermions in a finite box. Our calculation illustrates interesting issues facing the study of many-body states on the lattice, which may eventually be confronted in QCD calculations as well.Comment: 7 pages, 6 figures, The XXVIII International Symposium on Lattice Field Theory, Lattice2010, June 14-19, 2010, Villasimius, Ital

Simulation of transition dynamics to high confinement in fusion plasmas

The transition dynamics from the low (L) to the high (H) confinement mode in magnetically confined plasmas is investigated using a first-principles four-field fluid model. Numerical results are in close agreement with measurements from the Experimental Advanced Superconducting Tokamak - EAST. Particularly, the slow transition with an intermediate dithering phase is well reproduced by the numerical solutions. Additionally, the model reproduces the experimentally determined L-H transition power threshold scaling that the ion power threshold increases with increasing particle density. The results hold promise for developing predictive models of the transition, essential for understanding and optimizing future fusion power reactors

Lattice Monte Carlo calculations for unitary fermions in a finite box

We perform lattice Monte Carlo simulations for up to 66 unitary fermions in a finite box using a highly improved lattice action for nonrelativistic spin 1/2 fermions. We obtain a value of $0.366^{+0.016}_{-0.011}$ for the Bertsch parameter, defined as the energy of the unitary Fermi gas measured in units of the free gas energy in the thermodynamic limit. In addition, for up to four unitary fermions, we compute the spectrum of the lattice theory by exact diagonalization of the transfer matrix projected onto irreducible representations of the octahedral group for small to moderate size lattices, providing an independent check of our few-body simulation results. We compare our exact numerical and simulation results for the spectrum to benchmark studies of other research groups, as well as perform an extended analysis of our lattice action improvement scheme, including an analysis of the errors associated with higher partial waves and finite temporal discretization.Comment: Significant revisions from previous version. Included data at a larger volume and performed an infinite volume extrapolation of the Bertsch parameter. Published versio

Dynamic Analysis of UAV’s Motor Support Bar Length Control System

UAV (Unmanned Aerial Vehicle) can be described as aircraft that do not need any presence of pilots inside it. Basically, UAV is come out in a small aircraft sothat the aircraft can be easily controlled by the people from afar[1]. The UAV’s motor support bar length control systems are the UAV’s control systems that move according to the variable arm length movement and also a constant revolution of the propeller speeds. The purpose of the study is to run the dynamic analysis at the UAV’s motor support bar length control systems and also to enhance the UAV’s mathematical modellingby using the SOLIDWORKS®software which involved in using both CAD and CAE systems[2]. The detaileddesign is used SOLIDWORKS®software to conduct the static and dynamic analysis of UAV’s motor support bar length control systems. The design is restricted to the arm due to the critical part that has the highest vibration at the UAV’s motor support bar length control systems. The results that obtain from the study from the static and dynamic analysis are the displacement of the motor, Von Misses stress of the arm, and also the resonance frequency that will give the modes shape to the systems

Spin Waves in Random Spin Chains

We study quantum spin-1/2 Heisenberg ferromagnetic chains with dilute, random antiferromagnetic impurity bonds with modified spin-wave theory. By describing thermal excitations in the language of spin waves, we successfully observe a low-temperature Curie susceptibility due to formation of large spin clusters first predicted by the real-space renormalization-group approach, as well as a crossover to a pure ferromagnetic spin chain behavior at intermediate and high temperatures. We compare our results of the modified spin-wave theory to quantum Monte Carlo simulations.Comment: 3 pages, 3 eps figures, submitted to the 47th Conference on Magnetism and Magnetic Material

DEVELOPMENT OF RESEARCH FRAMEWORK FOR PBL PROBLEM SCENARIO USING LINEAR & NON-LINEAR MULTIMEDIA

Problem Based Learning (PBL) is an instructional approach to provide student with knowledge suitable for problem solving. To support the research, PBLStat courseware is developed based on the PBL approach. In PBL approach, problem scenario is first presented during the learning process. Problem scenario helps to maintain student interest in course so it is important to create a good problem that can cause students‘ inquiry and drive students to solve the problems. The purpose of this paper is to highlight the development of research framework for PBL problem scenario presentation. Problem scenario can be presented using linear and non-linear multimedia categories. The framework of study contains the description of research control modes, content and output. The control modes of the research are consisting of two independent variables which are linear problem scenario and non-linear problem scenario. Content is the phase of courseware‘s development. The ADDIE model is used to complete the development of courseware. Finally is the research output, this is to evaluate student‘s preferences and performances based on the problem scenario categorization. There are four research instrument tools has been created to answer the research question which are questionnaire, observation, interview and PBLStat

Designing Problem Based Learning (PBL) Problem Scenario for Statistic Using Linear and Non-linear Multimedia Presentation

Problem Based Learning (PBL) is an instructional method that is known to offer students with knowledge suitable for problem solving. In order to test this assertion the process of problem based learning is described and measured against three principle of learning: activation of prior knowledge, elaboration and encoding specificity. Using PBL method, students’ understanding with regards to the problem scenario is very significant process. One of the main defining characteristic of PBL, which distinguishes it from some other method, is that the problem is presented to the students first at the start learning process. Traditionally, problem scenario is presented in a printed text, which is not tempting for student to understand the motive behind it. Information and Communication Technology (ICT) on the other hand has widely accepted in many areas which include education as well. By applying multimedia presentation as a discipline in ICT, it is believed that it could helps in designing the effective problem scenario. The purpose of this study is to design and test the effectiveness of PBL problem scenario for subject Statistic using linear and non-linear multimedia presentation. Linear presentation is known as no navigation control is involved through that process while nonlinear presentation uses user interactivity to control the presentation. This paper discusses the early storyboard design and the icons that used