Page 5 - Physlets and Open Source Physics for Quantum Mechanics:

also be run as Java applications. The Launcher program shown in Figure 4 enables
authors to distribute collections of OSP programs and curricular material in consistent
self-contained packages. Launcher is designed to execute multiple Java applications
or multiple copies of a single Java application with different initial conditions. Launcher
also uses an XML file to store its properties, as shown in Figure 5.

<?xml version="1.0" encoding="UTF-8" ?>
<object class="org.opensourcephysics.tools.Launcher$LaunchSet">
<property name="classpath" type="string">demo200407.jar</property>
<property name="width" type="int">977</property>
<property name="height" type="int">650</property>
<property name="divider" type="int">220</property>
<property name="launch_nodes" type="collection"
class="java.util.ArrayList">
<property name="item" type="string">SuperpositionApp.xml</property>
<property name="item" type="string">Quantum2D.xml</property>
</property>
</object>

Figure 5: XML code for configuring the Launcher window shown
in Figure 4. The size of the Launcher window is set and the
SuperpositionApp.xml and Quantum2D.xml files are loaded. The
XML files contain the ‘outline’ information shown in the left-hand
panel of Figure 4.

Java-based curricular material has traditionally been distributed over the Internet using
applets. Sun Microsystems has recently released a new technology known as Java
Web Start that combines the applet and application approaches. Java Web Start is a
helper application that is associated with a Web browser. When a user clicks on a link
within an HTML page that points to a special file on the server, it causes the browser to
launch Java Web Start, which then automatically downloads, caches, and runs the
Java-based application. The entire process is typically completed without requiring any
user interaction, except for the initial single click. A number of Java Web Start
Launcher packages can be downloaded and run from the OSP Web site.

Quantum-mechanical Wave Packets

Wave Packet Revivals: Visualization

Time-dependent quantum-mechanical wave functions are inherently complex (having
real and imaginary components) due to the time evolution governed by the Schrödinger
equation. The standard way to visualize the wave function considers the probability
density in position or momentum space (more typically position space), an approach
that discards all phase information.

Figure 6: A free particle wave packet, initially moving to the right encounters an infinite
wall on the right before reflecting and moving to the left. The image depicts the
packet’s time evolution at equal-time intervals. The middle image corresponds to the
‘bounce:’ the time a classical particle would have hit the wall.