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Brusselator

Chemical oscillator — limit cycles and Hopf bifurcation

Parameters

State

[X]
[Y]
Fixed pt X*
Fixed pt Y*

Science

The Brusselator (Prigogine, 1968) is a minimal model for autocatalytic chemical oscillations:

dX/dt = A − (B+1)X + X²Y dY/dt = BX − X²Y

Fixed point: X* = A, Y* = B/A. Stability: eigenvalues of Jacobian at fixed point. Hopf bifurcation occurs at B = 1 + A².

B_Hopf = 1 + A²

For B > 1+A², the fixed point destabilizes and a stable limit cycle appears — the system oscillates indefinitely. This models the Belousov–Zhabotinsky reaction.