Cosmological Frequency Combs

We identify a new class of time periodic attractor solutions in scalar field cosmology, which we term Cosmological Frequency Combs (CFC). These solutions arise in exponential quintessence models with a phantom matter background and exhibit coherent phase-locked oscillations in the scalar field's normalized variables. We demonstrate that such dynamics induce modulations in observables like the Hubble parameter and growth rate, offering a dynamical mechanism to even address the H0 tension exactly. Our results uncover a previously unexplored phase of cosmic acceleration, linking the concept of frequency combs to large scale cosmological evolution.