Quantum Circuit Complexity as a Measure of Particle Creation in Bouncing Cosmologies
We investigate the evolution of circuit complexity for a quantum scalar field in a non-singular bouncing cosmological background. Unlike previous perturbative approaches, we utilize the Lewis-Riesenfeld invariant method to derive an exact non-perturbative framework for the complexity evolution across the bounce. We demonstrate that the complexity remains finite at the bounce, dominated by the squeezing of the quantum state due to spacetime contraction. Crucially, we find that the post-bounce growth of complexity exhibits a strong correlation with cosmological particle production. Our analysis reveals that the "chirping" contribution to complexity acts as a geometric memory of the transition, effectively quantifying the information cost of particle creation in non-trivial spacetime geometries.