Dynamics of Quadruple Systems Composed of Two Binaries: Stars, White Dwarfs, and Implications for Ia Supernovae

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[Abridged]We investigate the long-term secular dynamics and Lidov-Kozai(LK) eccentricity oscillations of quadruple systems composed of two binaries at quadrupole and octupole order in the perturbing Hamiltonian.

• We show that the fraction of systems reaching high eccentricities is enhanced relative to triple systems, over a broader range of parameter space.
• We show that this fraction grows with time, unlike triple systems evolved at quadrupole order.
• This is fundamentally because with their additional degrees of freedom, quadruple systems do not have a maximal set of commuting constants of the motion, even in secular theory at quadrupole order.