Bhattacharyya, ArpanArpanBhattacharyyaDas, SauryaSauryaDasHaque, S. ShajidulS. ShajidulHaqueUnderwood, BretBretUnderwood2025-08-312025-08-312020-05-1510.1103/PhysRevD.101.1060202-s2.0-85086001671https://d8.irins.org/handle/IITG2025/24152We 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 reentry, leading to a "decomplexification" of the Universe.trueArticlehttp://link.aps.org/pdf/10.1103/PhysRevD.101.1060202470002915 May 202055106020arJournal54WOS:000533499000010