Information Technology Reference
In-Depth Information
where
˃
y
is the Pauli spin matrix:
⊛
⊞
j
0010
0100
−
000
−
⊝
⊠
˃
y
=
.
(4)
j
00 0
3 The Application
QDsim was designed to solve the density matrix and compute the quantum
dynamics of concurrence as a function of time and a physical variable of the
QD system that is chosen by the user. For example, Fig. 2 shows in the vertical
axis, the concurrence, whose values oscillate between 0 and 1; the two horizontal
axes represent time (given in picoseconds) and the physical variable
VX
(e.g.,
the degree of purity of the Extended Werner-like state, probability amplitude,
the quotient between photon emission decay rate and radiative quantum dot
decay rate, the quotient between phonon emission decay rate and non-radiative
quantum dot decay rate, the quotient between dots coupling and dot-cavity
coupling. For more details about these variables, see [9] and [3].)
VX
Time
Fig. 2.
Surface plot of quantum concurrence
The system allows setting up different simulation parameters. The physical
variable to simulate (given by
VX
) is adjustable through a Graphical User Inter-
face (GUI) with their respective limits called
VLL
(
VX
Lower Limit) and
VUL
(
VX
Upper Limit) and the step increment (
VINC
). In addition, other variables
such as integration method, integration error, time intervals (
TLL
,
TUL
)and
other simulation variables can also be defined using the GUI.
The basic flow diagram of the application is composed of five tasks (see Fig.
3):
