JCApp's opening screen is pictured in Figure . The main menu's File and Help items have the same options as the other programs. The Field allows the user to change the state of the quantum field and also the number of states, as in FieldApp. The Numerical item sets various numerical parameters that control the simulation's algorithm.
Figure: Opening Screen for JCApp
The JCApp's two sliders alter the detuning, , and the coupling of the atom and field. As in BlochApp, the transition frequency of the atom has been defined to be one. The text readout above the sliders registers the evolution time. The buttons control the run state of the program.
JCApp has two analysis windows. The upper window is the field window and displays the state of the electromagnetic field. It has the same properties as the one in FieldApp. The lower window displays how the population of the atoms changes in time. The probability of the upper and lower states as well as the inversion may be plotted.
The algorithm for JCApp is based on eq:j11, eq:j12, eq:j13, and eq:j14. These four equations are solved n times, once for each field state specified. A Runge--Kutta four code has been used. A total of 4n equations are solved by JCapp, which is significantly more feasible than .