New on the Quantum Exchange

Nanohub

Tue, 06 Jan 2009 11:57:18 EST

NanoHUB is a web-based collection of resources for research, education and collaboration in nanotechnology. It contains online presentations, courses, learning modules, animations, and teaching materials. A focus of nanoHUB is the educational use of online simulation tools for nanotechnology devices. It is also a collaboration environment with group workspaces, online meetings and user groups. Nanohub resources come from a wide-range of contributors in the nanoscience community, and are used by thousands of users around the world. Nanohub is part of the Network for Computational Nanotechnology and is supported by the National Science Foundation through grants EEC-0228390 and EEC-0634750. It is also part of the NSF Cyberinfrastructure program.

Point Group Theory

Tue, 23 Dec 2008 13:20:03 EST

This is a reference web site for group theory and the properties of symmetry point groups. It covers the mathematics and science applications of symmetry relations, including the impact on interactions with specific reference to dipole-transition selection rules. Unit cells, stereograms, and 3D animated molecules are presented as examples of each point group. This web site also provides other symmetry related links and a link to references for symmetry in physics and chemistry.

Multiple Slit Diffraction Model

Mon, 22 Dec 2008 15:10:05 EST

The EJS Multiple Slit Diffraction model allows the user to simulate Fraunhofer diffraction through single or multiple slits. The user can modify the number of slits, the slit width, the slit separation and the wavelength of the incident light. The scale of the diffraction pattern can also be changed and a plot of the light intensity can be toggled on and off with a checkbox. A basic theoretical introduction to diffraction is included. The Multiple Slit Diffraction Model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_ntnu_optics_MultipleSlitDiffraction.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Open Source Physics programs for quantum mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or EJS.

Circular Well Superposition Model

Mon, 22 Dec 2008 15:07:29 EST

The Circular Well Superposition simulation displays the time evolution of the position-space wave function in an infinite 2D circular well. The default configuration shows the first excited state with zero angular momentum. Additional eigenstates can be added using a button in the eigenstate coefficient table. A description of the quantum system and eigenstates, with questions for the students, are included. Circular Well Superpostion Model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_qm_Superposition2DCircularWell.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Open Source Physics programs for quantum mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or EJS.

Special Functions Model

Mon, 22 Dec 2008 15:01:02 EST

EJS Special Functions Model shows how to access special functions in the OSP numerics package. The simulation displays a graph of the specail function over the given range as well as the value of the selected function at single point. The following special functions can be displayed:

Legendre polynomials Pn(x)
associated Legendre functions Pnm(x)
Laguerre polynomials Ln(x)
associated Laguerre polynomials Lnm(x)
Chebyshev polynomials of the first kind Tn(x)
Chebyshev polynomials of the second kind Un(x)
Bessel functions Jn(x)

A description of the EJS special functions along with links to more information about the functions are provided.

Physlet Problems Written or Adapted by Paul Zitzewitz

Tue, 04 Nov 2008 15:56:09 EST

This collection of physics applets (Physlets) covers topics in electric and magnetic fields, osmosis, and quantum physics. Each Java animation includes text and exercises directing student activity. The quantum materials include solutions to 1D harmonic oscillator and square well potentials, and angular and radial states of hydrogenic orbitals. This material is based on the development of Physlets by Wolfgang Christian.

Resources Students Use to Understand Quantum Mechanical Operators

Tue, 04 Nov 2008 15:52:35 EST

The Paradigms team at Oregon State University has developed a quantum mechanics curriculum aimed at middle division students that begins with a strong emphasis on using operators, matrices and Dirac notation to describe quantum systems. The curriculum begins with spin systems, and this content ordering relies on students being able to understand quantum mechanical operators, eigenstates and quantum measurement without prior instruction on wave functions. We have analyzed classroom and an interview video to identify resources students use when considering these quantum ideas. Identification of such resources will inform introductory curricula that are prerequisite to the quantum Paradigms and inform the development of Paradigms materials that will guide students to use these resources productively.

Eigenstate Superposition

Sun, 31 Aug 2008 19:05:52 EST

This applet illustrates the fundamental building blocks of one-dimensional quantum mechanics, the energy eigenfunctions ψ_n(x) and energy eigenvalues E_n. The user enters the expansion coefficients into a table and the simulation uses the superposition principle to construct and display a time-dependent wave function using either infinite square well (ISW) or simple harmonic oscillator (SHO) eigenfunctions.

PhET Simulation: Quantum Physics

Mon, 11 Aug 2008 13:00:12 EST

This is a collection of simulations from the PhET project in Quantum and Modern Physics. The simulations cover a range of topics including the photoelectric effect, wave interference, lasers, blackbody radiation, tunneling, the Stern-Gerlach experiment, nuclear physics, and applications of quantum mechanics. Each simulation provides a user interface that allows learners to explore the physical systems. These resources are part of the PhET project that has created a large collection of research-validated physics, chemistry, and math simulations.

How does Quantum Mechanics turn into Classical Mechanics?

Mon, 11 Aug 2008 12:31:36 EST

This website contains a short tutorial on the time dependent Schrodinger Equation and the motion of wave packets. The dynamics of a compact wavepacket in a square well serves as a connection with the classical limit. A JAVA applet allows the user to control parameters of the wavepacket. The website includes suggested instructive activities. Note, the applet does not run as an animation; the user must manually increment time.

Teaching Quantum Theory in the Introductory Course

Thu, 12 Jun 2008 12:28:47 EST

This journal article argues that it is important to introduce quantum theory in college freshman physics classes. The author shows from experience how a teacher can teach the subject without using advanced mathematics and provides specific strategies, along with examples, on the most effective ways to introduce various quantum principles. These examples include the photoelectric effect, particle theory of radiation, wave-matter duality, the quantum atom, uncertainty principles, interconnectedness principle, and the Copenhagen interpretation.

A Quantum Bouncing Ball

Tue, 13 May 2008 17:34:22 EST

This animation shows the quantum analogy of a classical bouncing ball moving in a gravitational field, without dissipation. The video shows the wave packet motion next to the ball. A graph of the expectation value of the quantum ball versus time is provided that illustrates the dispersion and later reforming of the quantum wave packet.

Open Source and Open Access Resources for Quantum Physics Education

Mon, 28 Apr 2008 14:02:14 EST

Quantum mechanics is both a topic of great importance to modern science, engineering, and technology, and a topic with many inherent barriers to learning and understanding. Computational resources are vital tools for developing deep conceptual understanding of quantum systems for students new to the subject. This article outlines two projects that are taking an open source/open access approach to create and share teaching and learning resources for quantum physics. The Open Source Physics project provides program libraries, programming tools, example simulations, and pedagogical resources for instructors wishing to give a rich experience to their students. These simulations and student activities are, in turn, being integrated into a world?wide collection of teaching and learning resources available through the Quantum Exchange, a part of the ComPADRE Portal to the National Science Digital Library. Both of these projects use technologies that encourage community development and collaboration. Using these tools, faculty can create learning experiences, share and discuss their content with others, and combine resources in new ways. Examples of the available content and tools are given, along with an introduction to accessing and using these resources.

QM Momentum Measurement Program

Thu, 17 Apr 2008 00:19:25 EST

The QM Momentum Measurement program displays the time evolution of the position-space wave function and can be used to simulate the quantum-mechanical measurement of momentum to a finite precision. The default wave function is an equal-mix four-state superposition in the infinite square well. QM Momentum Measurement is one of 18 Open Source Physics programs that model time-dependent quantum mechanics using an energy eigenstate expansion. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the qm_measurement_p.jar file will run the program if Java is installed. Other programs provide additional visualizations. They can be found by searching ComPADRE for Open Source Physics, OSP, or Superposition.

QM Position Measurement Program

Thu, 17 Apr 2008 00:15:51 EST

The QM Position Measurement program displays the time evolution of the position-space wave function and can be used to simulate the quantum-mechanical measurement of position to a finite precision. The default wave function is an equal-mix four-state superposition in the infinite square well. QM Position Measurement is one of 18 Open Source Physics programs that model time-dependent quantum mechanics using an energy eigenstate expansion. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the qm_measurement_x.jar file will run the program if Java is installed. Other programs provide additional visualizations. They can be found by searching ComPADRE for Open Source Physics, OSP, or Superposition.

QM Energy Measurement Program

Thu, 17 Apr 2008 00:12:17 EST

The QM Energy Measurement program displays the time evolution of the position-space wave function and can be used to simulate the quantum-mechanical measurement of energy. The default wave function is an equal-mix four-state superposition in the infinite square well. QM Energy Measurement is one of 18 Open Source Physics programs that model time-dependent quantum mechanics using an energy eigenstate expansion. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the qm_measurement_e.jar file will run the program if Java is installed. Other programs provide additional visualizations. They can be found by searching ComPADRE for Open Source Physics, OSP, or Superposition.

QM Wigner Program

Wed, 16 Apr 2008 23:37:24 EST

The QM Wigner program displays the time evolution of the position-space wave function and the associated quasi-probability distribution in phase space via the Wigner function. The default wave function is a Gaussian wave packet in a harmonic oscillator. Additional states and other potential energy functions can be specified using the Display | Switch GUI menu item. QM Wigner is one of 18 Open Source Physics programs that model time-dependent quantum mechanics using an energy eigenstate expansion. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the qm_wigner.jar file will run the program if Java is installed. Other programs provide additional visualizations. They can be found by searching ComPADRE for Open Source Physics, OSP, or Superposition.

QM Momentum Carpet Program

Wed, 16 Apr 2008 23:16:15 EST

The QM Momentum Carpet program displays the time evolution of the position-space wave function and the associated quantum-mechanical momentum-time diagram, the momentum-space quantum carpet. The default wave function is a Gaussian wave packet in an infinite square well. Additional states and other potential energy functions can be specified using the Display | Switch GUI menu item. QM Momentum Carpet is one of 18 Open Source Physics programs that model time-dependent quantum mechanics using an energy eigenstate expansion. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the qm_momentun_carpet.jar file will run the program if Java is installed. Other programs provide additional visualizations. They can be found by searching ComPADRE for Open Source Physics, OSP, or Superposition.

QM Carpet Program

Wed, 16 Apr 2008 23:09:27 EST

The QM Carpet program displays the time evolution of the position-space wave function and the associated quantum-mechanical space-time diagram, the quantum carpet. The default wave function is a Gaussian wave packet in an infinite square well. Additional states and other potential energy functions can be specified using the Display | Switch GUI menu item. QM Carpet is one of 18 Open Source Physics programs that model time-dependent quantum mechanics using an energy eigenstate expansion. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the qm_carpet.jar file will run the program if Java is installed. Other programs provide additional visualizations. They can be found by searching ComPADRE for Open Source Physics, OSP, or Superposition.

QM Momentum Space Program

Wed, 16 Apr 2008 22:43:28 EST

The QM Momentum Space program displays the time evolution of the position-space wave function and the associated momentum-space wave function. The default wave function is a Gaussian wave packet in a harmonic oscillator. Additional states and other potential energy functions can be specified using the Display | Switch GUI menu item. QM Momentum Space is one of 18 Open Source Physics programs that model time-dependent quantum mechanics using an energy eigenstate expansion. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the qm_fft.jar file will run the program if Java is installed. Other programs provide additional visualizations. They can be found by searching ComPADRE for Open Source Physics, OSP, or Superposition.