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Full-Text Articles in Physics

Scalability Improvements To Nrlmol For Dft Calculations Of Large Molecules, Carlos Manuel Diaz Jan 2016

Scalability Improvements To Nrlmol For Dft Calculations Of Large Molecules, Carlos Manuel Diaz

Open Access Theses & Dissertations

Advances in high performance computing (HPC) have provided a way to treat large, computationally demanding tasks using thousands of processors. With the development of more powerful HPC architectures, the need to create efficient and scalable code has grown more important. Electronic structure calculations are valuable in understanding experimental observations and are routinely used for new materials predictions. For the electronic structure calculations, the memory and computation time are proportional to the number of atoms. Memory requirements for these calculations scale as N2, where N is the number of atoms. While the recent advances in HPC offer platforms with large numbers ...


Strongly Coupled Quark Matter: Chiral Symmetry Breaking In A Magnetic Field, And Eos In The Bec-Bec Crossover, Israel Portillo Vazquez Jan 2014

Strongly Coupled Quark Matter: Chiral Symmetry Breaking In A Magnetic Field, And Eos In The Bec-Bec Crossover, Israel Portillo Vazquez

Open Access Theses & Dissertations

We explore chiral symmetry breaking in a magnetic field within a Nambu-Jona-Lasinio model of interacting massless quarks including tensor channels. The new interaction channels are opened up through Fierz identities due to the breaking of the rotational symmetry by the magnetic field. We demonstrate that the magnetic catalysis of chiral symmetry breaking leads to the generation of two independent condensates, the conventional chiral condensate and a spin-one condensate. While the chiral condensate generates a dynamical fermion mass, the spin-one condensate gives rise to a dynamical anomalous magnetic moment for the fermions. We also investigate the possibility of a crossover from ...


Upgrades To Nrlmol Code, Luis Basurto Jan 2013

Upgrades To Nrlmol Code, Luis Basurto

Open Access Theses & Dissertations

This project consists of performing upgrades to the massively parallel NRLMOL electronic structure code in order to enhance its performance by increasing its flexibility by: a) Utilizing dynamically allocated arrays, b) Executing in a parallel environment sections of the program that were previously executed in a serial mode, c) Exploring simultaneous concurrent executions of the program through the use of an already existing MPI environment; thus enabling the simulation of larger systems than it is currently capable of performing. Also developed was a graphical user interface that will allow less experienced users to start performing electronic structure calculations by aiding ...


Upgrades To Nrlmol Code, Luis Basurto Jan 2012

Upgrades To Nrlmol Code, Luis Basurto

Open Access Theses & Dissertations

This project consists of performing upgrades to the NRLMOL code in order to enhance its performance by increasing its flexibility by utilizing dynamically allocated arrays and enable the simulating of larger systems than it's currently capable of executing, as well as exploring simultaneous concurrent executions of the program through the use of an already existing MPI environment.


Pressure Induced Phase Transformation Of Sno2: An Ab Initio Constant Pressure Study, Daniel Tesfai Yehdego Jan 2009

Pressure Induced Phase Transformation Of Sno2: An Ab Initio Constant Pressure Study, Daniel Tesfai Yehdego

Open Access Theses & Dissertations

The behavior of SnO2 under rapid hydrostatic pressures is studied using constant-pressure ab initio simulations. The rutile-type SnO2 gradually transforms into the CaCl2-type structure at 15 GPa. At a pressure of about 20 GPa, a phase transformation into a cubic fluorite-type structure is observed. The orthorhombic Pnma cotunnite-structured phase is observed above 150 GPa. The mechanisms of these phase transformations at the atomistic level are discussed.