Bhattacharyya, ArpanArpanBhattacharyyaDas, SauryaSauryaDasHaque, S. ShajidulS. ShajidulHaqueUnderwood, BretBretUnderwood2025-08-222025-08-222020-01-012331-8422http://arxiv.org/abs/2001.08664https://d8.irins.org/handle/IITG2025/18344We compute the quantum circuit complexity of the evolution of scalar curvature perturbations on expanding backgrounds, using the language of squeezed vacuum states. In particular, we construct a simple cosmological model consisting of an early-time period of de Sitter expansion followed by a radiation-dominated era and track the evolution of complexity throughout this history. During early-time de Sitter expansion the complexity grows linearly with the number of e-folds for modes outside the horizon. The evolution of complexity also suggests that the Universe behaves like a chaotic system during this era, for which we propose a scrambling time and Lyapunov exponent. During the radiation-dominated era, however, the complexity decreases until it "freezes in" after horizon re-entry, leading to a "de-complexification" of the Universe.en-USHigh Energy Physics - Theory (hep-th)General Relativity and Quantum Cosmology (gr-qc)Quantum Physics (quant-ph)e-Printe-Print123456789/615