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Quantum Magnetism Analysis Model Documents

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Main Document

Quantum Magnetism Analysis Model 

written by Larry Engelhardt, Chad Garland, Cameron Rainey, and Austin Freeman

The Quantum Magnetism Analysis Model was created to help students as well as researchers who are studying magnetism.  It provides a very simple interface for defining (theoretical) quantum spin models; sliders are automatically created to vary the parameters in the models; and several plots are automatically created to visualize the results.  Within the program, several measured (experimental) data sets are included for a variety of real molecules.  These provide the opportunity to experience the modeling process by varying the parameters in the model and exploring how the simulated results compare to the measured data.

The interactions between neighboring quantum magnetic moments ("spins") are modeled using the Heisenberg model; calculations are carried out by numerically diagonalizing the matrix representation of the Heisenberg Hamiltonian; and plots display the energy spectrum, magnetization, and magnetic susceptibility as a function of temperature and magnetic field.

This simulation is a "Fully Integrated Tool for Magnetic Analysis in Research & Teaching," so we also refer to it with the acronym "FIT-MART".  FIT-MART was developed using the Easy Java Simulations (EJS) modeling tool.  It is distributed as a ready-to-run (compiled) Java archive.  Double clicking ejs_fitmart.jar file will run the package if Java is installed.  In future versions of this simulation, curricular materials will be included to help students to learn about magnetism, and automated fitting routines will be included to help researchers quickly and easily model experimental data.


FIT-MART was developed using the Easy Java Simulations (EJS) modeling tool.  It is distributed as a ready-to-run (compiled) Java archive.  Double clicking ejs_fitmart.jar file will run the package if Java is installed.

Published July 27, 2012
Last Modified September 7, 2013

This file has previous versions.

Supplemental Documents

FIT-MART: Quantum Magnetism with a Gentle Learning Curve 

The FIT-MART: Quantum Magnetism with a Gentle Learning Curve paper describes how to use FIT-MART to quickly get started simulating quantum magnetism. FIT-MART can be downloaded as a platform-independent executable Java (JAR) le. It allows the user to define (Heisenberg) Hamiltonians by electronically drawing pictures that represent quantum spins and operators. Sliders are automatically generated to control the values of the parameters in the model, and when the values change, several plots are updated in real time to display both the resulting energy spectra and the equilibrium magnetic properties. Several experimental data sets for real magnetic molecules are included in FIT-MART to allow easy comparison between simulated and experimental data, and FIT-MART users can also import their own data for analysis and compare the goodness of fit for different models.

Last Modified July 8, 2013

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Source Code Documents

Quantum Magnetism Analysis Source Code 

The source code zip archive contains an XML representation of the Quantum Magnetism Analysis Model.  Unzip this archive in your EJS workspace to compile and run this model using EJS.

Last Modified September 7, 2013

This file has previous versions.

The OSP Network:
Open Source Physics - Tracker - EJS Modeling
Physlet Physics
Physlet Quantum Physics