Gary Wysin, Condensed Matter Physics
Magnetism and Optics Theory and Simulation


The Beira Mar, Florianópolis, Santa Catarina, Brazil, 2005.

Last sabbatical leave 2011 - 2012 at
Universidade Federal de Santa Catarina, Florianopólis, Brazil.
working in the Department of Physics

and earlier at
Universidade Federal de Viçosa, Minas Gerais, Brazil.

Permanent address: 309 Cardwell Hall, Department of Physics,
Kansas State University, Manhattan KS 66506-2601, USA.
(785) 532-1628 / FAX: (785) 532-6806

Best way to contact me: wysin@phys.ksu.edu

Curriculum Vita on the Lattes system in Brazil

Google Scholar Profile and Citations

ResearcherID Profile and Citations

New Book:
Statistical Thermodynamics: Understanding the Properties of Macroscopic Systems
Lukong Cornelius Fai and Gary Matthew Wysin

Taylor & Francis, October, 2012

Congratulations, however you did it, you found me! If you are interested in theoretical physics, or in making computer simulations in physics, or just want to know what I am doing, this is a good place to start.

There's an interesting world of magnetism, from the very applied, such as all those MegaBytes of magnetic disk storage you are now using, to the very abstract, which includes solitons and vortices. I use a combination of mathematical physics, statistical physics, solid state physics, quantum mechanics, and common sense to figure out how to get computers to calculate what I want to know about various magnetic materials. It is all based on models of interacting spins on a lattice, which are the microscopic magnetic moments (arrows) that can cooperate to form what we see in magnetized objects, usually by all trying to be parallel.

What I do in physics:

Teaching:

Disclaimer: If you can't see any problem solutions for some class, unfortunately I had to limit the access for one reason or another, sorry!!! That way you will have more pleasure working the problems out yourself!

Physical World I 101
Introductory course on many topics in science, especially physics and chemistry. Go here to see Review Questions and Problems and other Physical World I information.
General Physics I Lecture 113
2007-2012 course. Motion, mechanics, energy, waves and thermodynamics. Lecture notes and Exam solutions.
General Physics II Lecture 114
2007-2012 course. Electricity, magnetism, optics, quantum and nuclear physics. Lecture notes and Exam solutions.
General Physics II Recitation 114
Electricity, magnetism, and beyond. Brief summaries of the concepts and formulas for important topics.
Descriptive Astronomy 191
Go here to see Review Questions and Problems and other Introductory Astronomy information.
Engineering Physics I Lecture/Studio 213/223
Newton's Laws, thermodynamics, work, energy and all that. Go here to see my scribblings of solved EPI physics problems, and other EPI information. From Spring 2004.
Engineering Physics II Lecture 214/224
Electric and magnetic fields, circuits, optics. Go here to see my EPII lecture notes and other information. From Fall 2003.
Applied Quantum Mechanics 709
Overview of basic applications of quantum mechanics in modern physics. Go here to see my lecture notes and other information.
Physics Journal Club 806
Fall 2005 course. Click to see the schedule of teaching and research talks that took place.
Mathematical Methods for Physicists 801
Advanced mathematical techniques for solving theoretical physics problems.
Quantum Mechanics-I 811
Graduate level quantum mechanics. Fundamentals, Schrodinger Eqn., wavefunctions, representations, etc.
Quantum Mechanics-II 911
Graduate level quantum mechanics. Scattering, spin, rotations, perturbation theory, introduction to relativistic theory.
Electrodynamics-I 831
Fall 2005 course. Graduate level analysis/application of Maxwell's equations, advanced mathematical techniques for elecrostatics, magnetostatics, time-dependent fields, electromagnetic waves.
Electrodynamics-II 931
Spring 2006 course. Graduate level analysis/application of Maxwell's equations for electromagnetic radiation from antennas and moving particles, relativistic EM fields.
Statistical Thermodynamics: Understanding the Properties of Macroscopic Systems
Description of book to be published at Taylor & Francis, October, 2012. A graduate level text on thermodynamics and statistical mechanics with applications in classical and quantum statistics of ideal gases, lattice dynamics, electron gas, dielectrics, magnetism, semiconductors, superfluids, functional integration and path integrals.

Research:

Some short descriptions of recent and not-so-recent work.
Publications
My recent and not so recent papers, proceedings articles, and zipped RevTex preprints.
Optical Bistability with Surface Plasmons
Master's Thesis, Gary M. Wysin, Department of Physics, University of Toldeo, 1980.
Oriented by R.T. Deck and H.J. Simon.
Classical Kink Dynamics and Quantum Thermodynamics in Easy-Plane Magnetic Chains with an Applied Magnetic Field
Ph.D. Thesis, Gary M. Wysin, Department of Physics, Cornell University, 1985.
Oriented by J.A. Krumhansl and A.R. Bishop.
Current and Past Funding
My thanks to KSU, NSF, NSF-EpsCoR, NAS/NRC, CNPq and FAPEMIG for their support.
Research Experiences for Undergraduates, Summer 2008
Introductory information about a project on control of magnetic vortex properties.
Physics Research Topics
Some of the physics problems I've worked on, concerning vortices, domain walls, fine magnetic particles, and their hysteresis.
Computational Techniques and Simulations
How some of the calculations are done, including Monte Carlo, Spin Dynamics, and Numerical Diagonalization.
Optical Modes in Micro-Cavities (see image -->)
Diagrams of the vibrations of electromagnetic fields (or elastic membranes like drums!) when constrained to occur within equilateral triangles or hexagons. Nice wavefunction plots!
Vortex-Spinwave Scattering Results
Some technical notes on my calculations of the spectrum of spinwaves in the presence of a magnetic vortex in two dimensions.
Notes on Numerical Quantum Mechanics
Some technical notes on recent Quantum Monte Carlo methods for spin models.

Physics Notes:

Some notes on graduate level physics problems. These might be of interest to graduate students in physics, chemistry, engineering and related fields. Knowledge of quantum mechanics, statistical mechanics, and electrodynamics is assumed for most of these notes.
Quantization of the Free Electromagnetic Field: Photons and Operators
The main ideas and equations for quantized free electromagnetic fields are developed and summarized here, based on the quantization procedure for coordinates (components of the vector potential A) and their canonically conjugate momenta (components of the electric field E).
Probability Current and Current Operators in Quantum Mechanics
A quantum particle such as an electron produces electric current because of its motion. That current is associated with the flow of its probability. The formalism to discuss quantum currents, in terms of density matrix ideas, is discussed here.
Quantum Theory for Dielectric Properties of Conductors A. Response to Optical Electric Field Only
The complex and frequency-dependent dielectric function ε(ω) describes how light interacts when propagating through matter. Of particular interest here is the description of ε(ω) in conductors using quantum mechanics, so that intrinsically quantum mechanical systems can be described. This part A leads to a description of the contributions from band-to-band transitions, such as in metals and semiconductors.
Quantum Theory for Dielectric Properties of Conductors B. Magnetic Fields and Landau Levels
In part B, the important problem is how to include the effect of a DC magnetic field in the dielectric function, and describe how it causes Faraday rotation. One possible effect of the magnetic field is that it produces quantized Landau levels for the eletrons. The dielectric function ε(ω) for a free electron gas is found, using the Landau levels.
Quantum Theory for Dielectric Properties of Conductors C. Effects of Magnetic Fields on Band-To-Band Transitions
In part C, the quantum effects of a DC magnetic field on the band-to-band transitions, such as those in metals and semiconductors, are discussed. Results for ε(ω) are found for 1D and 3D band models, with and without a phenomenolgical damping.
Associated Legendre Functions & Dipole Transition Matrix Elements
Notes on Legendre polynomials, associated Legendre functions, spherical harmonics, and the properties needed from them to get electric dipole transition matrix elements. Possibly useful where a problem involves electric dipole transitions and the matrix elements are desired.
Stochastic Spin Dynamics & Langevin-Landau-Gilbert Simulations
The dynamics of microscopic systems, primarily for spin models in thermal equilibrium is discussed, where the temperature causes random forces or torques, which are in competition with a damping force. This includes summarizing Langevin dynamics and finding methods for integrating the Landau-Gilbert equation of micromagnetics in time, with damping and temperature.
Demagnetization fields
A discussion of the magnetic fields inside and around a magnet, that are caused by that magnet. Mainly considers a permanent magnet of cylindrical shape. Also shows how to get effective Green's functions for finding the magnetic field inside a very thin magnet with an arbitrary magnetization, as would be needed in some micromagnetics simulations of thin-film magnets.
Pythagorean Theorem Proofs
No physics here. Just for fun, two simple and diferent proofs of the Pythagorean theorem for right triangles, a2+b2=c2. If you have others, let me know!

Physics Graphics Simulations with C/X11-Programming

These are some visualization programs I wrote for physics fun. They are great for seeing the dynamics in some simple systems. You'll need a c-compiler, UNIX and X11 libraries to compile and run them. See the first few lines of the main programs to get the compile command. Hit the 'h' key to get a window showing the key-touch commands (click the program images here to see that). These should run on Linux, Apple, and other unix systems.

xgrph.zip: A UNIX X11 xy-plotting program.

A UNIX c-program that quickly opens a window and draws plots of xy data from data files given to it. It's a fast alternative to using gnuplot or xvgr/xmgr. Hit 'h' for help window which shows all single keyboard stroke commands. Includes 'p' and 'l' for portrait or landscape PostScript printout.

Source code in C/X11 is here: xgrph.zip. For a sample data file, click --> sample_data . If you use it and find bugs please report them to me at wysin@phys.ksu.edu.

Typical graph drawn by xgrph with data for multiple curves inputted from several files.

xorbit.c: A Planetary Orbit Simulation Program

A UNIX c-program that gives graphical demonstration of elliptical planetary orbits. For C/X11 source code click here: xorbit.c.

The radius from Sun to planet sweeps out equal areas in equal times, Kepler says.

gas2d.zip: A 2-Dimensional Gas Simulation Program

A UNIX c-program that simulates motion and collisions of a mixture of 2D balls, with gravity, time-reversal, and pressure and rms speed measurement. For C/X11 source code click here: gas2d.zip.

Light, intermediate, and heavy balls in thermal equilibrium in a gravitational field, from gas2d simulation.

rotor.zip: Planar-rotor Model for a Magnet

A UNIX c-program that simulates a magnet made of 2D planar rotors under the influence of temperature and applied magnetic field. It shows the magnetization changes, using Metropolis Monte Carlo or Langevin spin dynamics. Made in collaboration with the PhET project at University of Colorado , with support of a 2010 Big 12 Faculty Fellowship from Kansas State University. See a short report on my Big 12 Fellowship activities. The program source code is here: rotor.zip (Planar-Rotor Magnet).

Planar rotor dipoles and the field they produce for a magnet at low temperature. The large red arrow is the net magnetization. There is no applied field. The rotors start to form domains, due to dipole-dipole interactions.

xmc.zip: A Monte Carlo and Spin Dynamics Simulation Program

A UNIX c-program that demonstrates how the spins and vortices in a magnet move around under the influence of temperature only (xmc) or under temperature and time (xmd). Source code is here: xmc.zip (Monte Carlo with spin dynamics).

Simulation of anisotropic Heisenberg model near its critical temperature, showing calculations of absolute magnetic moment in XY plane, susceptibility, internal energy, specific heat, and vorticity density. Blue/white arrows indicate spins with +/- components out of the XY plane. Red +/- indicate vortices/antivortices.


Other Information:

Co-workers on these projects
It's a small world. These are some of the people I visit and work with.
Physics photo album
Interesting pics of our world.
A local photo album
My art work.

Physics Department:


Other Links At KSU:


[Error Creating Counter File] since 2006/02/10.


Last update: Friday January 11 2013.
email to --> wysin@phys.ksu.edu


GMW at the Konza Prairie, July 1995.