  We investigate the effect of time delay on the dynamical model of love. The
local stability analysis proves that the time delay on the return function can
cause a Hopf bifurcation and a cyclic love dynamics. The condition for the
occurrence of the Hopf bifurcation is also clarified. Through a numerical
bifurcation analysis, we confirm the theoretical predictions on the Hopf
bifurcation and obtain a universal bifurcation structure consisting of a
supercritical Hopf bifurcation and a cascade of period-doubling bifurcations,
i.e., a period doubling route to chaos.
