Sermet Cagan delivered an online seminar hosted by the Center for Quantum Spacetime (CQUeST) at Sogang University, Korea. The presentation focused on the cosmological implications of O(D, D)-symmetric Friedmann equations derived from string-inspired gravity. The talk explored stability analysis, critical points, and flux-driven acceleration phases, offering a fresh perspective on open universe configurations and challenging conventional models.

The seminar delved into the O(D, D)-symmetric extensions of Friedmann equations, a theoretical framework rooted in Double Field Theory. By applying a dynamical systems approach, Sermet Cagan identified critical points and stability regions in scalar field, radiation, and matter-dominated universes. The analysis revealed flux contributions as pivotal drivers of novel acceleration dynamics, favoring open universe for some configurations over standard flat models.

Key highlights of the presentation included:

• A comparative analysis of O(D, D)-symmetric gravity with the phenomenological Chameleon cosmology, showcasing distinct theoretical predictions.
• Insights into acceleration phases without invoking dark energy, offering a compelling alternative to the \LambdaCDM paradigm.
• Theoretical implications of symmetry in addressing unresolved questions about early- and late-universe dynamics.

The engaging talk fostered discussions on the potential of O(D, D)-symmetric gravity to reshape our understanding of cosmic acceleration. Hosted virtually by CQUeST, this seminar underscored the relevance of string-inspired cosmological models in advancing modern theoretical physics.