Windows of periodicity scaling
It is a commonly observed feature of chaotic dynamical systems  that, as a
system parameter is varied, a stable period-n orbit appears (by a
tangent bifurcation) which then undergoes a
period-doubling cascade to chaos and finally
terminates via a crisis (in which the unstable
period-n orbit created at the original tangent bifurcation collides with the
n-piece chaotic attractor). This parameter range between the tangent
bifurcation and the final crisis is called a period-n window.
Note, that the central part of the picture below is similar to the whole
bifurcatin diagram (see two pictures at the bottom of the page).
You can test below that in the vicinity of c3 = -1.75488
the map fc o3 is "quadratic-like" and iterations
of the map repeat bifurcations of the original quadratic map
fc . This sheds light on the discussed similarity of
windows of periodicity.
Set a new c value (and press Enter) to see an animation or
set N = 1 to watch iterations of fc .
The width of a window. "Linear"
Consider a period-n window. Under iterations the critical orbit consecutively
cycles through n narrow intervals S1 -> S2
-> S3 -> ... -> S1 each of width
sj (we choose S1 to include the critical
point x = 0).
where Ln =
...ln is the product of the map
slopes, lj = 2xj
in (n-1) noncentral intervals and b =
1 + l2-1 +
... + Ln-1 ~ 1
for large Ln .
We take Ln at
c = cc and treat it as a constant in narrow window.
we expand fcon(x) for small x (in the
narrow central interval S1) and c near its value
cc at superstability of period-n attracting orbit.
We see that the sj are small and the map in the intervals
S2, S2, ... Sn may be regarded as
approximately linear; the full quadratic map must be retained for
the central interval. One thus obtains
xj+n ~ Ln
[xj2 + b(c - cc )] ,
Introducing X = Ln x and
C = b Ln2
(c - cc ) we get quadratic map
Xj+n ~ Xn2 + C
Therefore the window width is
while the width of the central interval scales as
For the biggest period-3 window
L3 = -9.29887 and
b = 0.60754. So the central band is reduced
~ 9 times and reflected with respect to the x = 0 line as we have
seen before. The width of the window is reduced
= 52.5334 times.
On the left picture below you see the whole bifurcation diagram of
fc . Similar image to the right is located in the centeral
band of the biggest period-3 window and is stretched by
9 times in the horizontal x and by 54 times in the
vertical c directions.
 J.A.Yorke, C.Grebogi, E.Ott, and L.Tedeschini-Lalli
"Scaling Behavior of Windows in Dissipative Dynamical Systems"
Phys.Rev.Lett. 54, 1095 (1985)
 B.R.Hunt, E.Ott
Structure in the
Parameter Dependence of Order and Chaos for the Quadratic Map
J.Phys.A 30 (1997), 7067.
Previous: Quaternions & the Mandelbrot set
Next: Renormalization on complex plane
updated 22 Sept 2002