Particle in a Double-Well Potential

Visualizing the conservative system from Example 6.5.2: $\ddot{x} = x - x^3$.
Top graph: Phase Plane ($y$ vs $x$). Bottom graph: Potential Energy Well ($V$ vs $x$).
Active Trajectory
Particle
Background Flows
Min: -0.25 (Centers), 0.0 (Saddle)
System Equations:
Potential: $V(x) = -\frac{1}{2}x^2 + \frac{1}{4}x^4$
Energy: $E = \frac{1}{2}y^2 + V(x)$
Dynamics: $\dot{x} = y$, $\dot{y} = x - x^3$
Physics Note:
Notice how the particle oscillates within one well when $E < 0$, follows the homoclinic orbit (figure-8) at $E \approx 0$, and encircles both wells when $E > 0$.