Strings, Gravity and Applications to Cosmology and Strong Coupling

This award funds the research activities of Professors Timm Wrase and Sera Cremonini at Lehigh University. One of the deepest challenges in modern science is to reconcile gravity, which governs stars, black holes, and the evolution of the universe, with quantum mechanics, which governs nature at the smallest scales. String theory, the leading candidate for a theory of quantum gravity, provides a framework for addressing this challenge. Holography, a related set of ideas connecting gravitational systems to quantum systems without gravity, offers powerful tools for understanding quantum matter whose constituents interact too strongly for conventional calculational methods to work. Under this award, Professors Wrase and Cremonini will investigate which low-energy laws of physics can be consistent with quantum gravity, how string theory can illuminate inflation and dark energy, how black holes encode and process quantum information, and how holographic methods can reveal universal properties of strongly interacting quantum phases of matter. The intellectual merit of the project lies in connecting fundamental questions about spacetime and cosmology to potential observational signatures and to the dynamics of systems ranging from the quark-gluon plasma of the early universe to unconventional electronic materials. The research may sharpen theoretical targets for cosmological measurements, improve our understanding of black holes and quantum information, and identify principles governing the flow of energy and charge in strongly correlated matter. Research in this area advances the national interest by promoting the progress of science in one of its most fundamental directions: discovering and understanding the laws that govern matter, spacetime, and the universe, while developing knowledge relevant to quantum information science and, over the longer term, quantum materials. The project’s broader impacts include research training for graduate and undergraduate students; the integration of new results into courses on cosmology, string theory, quantum field theory, black holes, quantum gravity, and quantum information; and undergraduate research opportunities through Lehigh’s Research Experiences for Undergraduates program. Professors Wrase and Cremonini will give public lectures and organize activities for school students, including mentoring and outreach designed to encourage students from a wide range of backgrounds to pursue physics and other STEM fields. More technically, Professors Wrase and Cremonini will combine analytical calculations and targeted numerical work using methods from string theory, quantum field theory, general relativity, effective field theory, and holography. They will refine swampland conjectures and derive constraints on low-energy effective field theories from causality, unitarity, analyticity, and positivity. Their analysis will use higher-derivative interactions, shockwave backgrounds and black hole extremality bounds to test connections between causality and the Weak Gravity Conjecture, to extend analyses of long-range forces and positivity bounds to anti-de Sitter and de Sitter spacetimes, and to seek new constraints on the properties of dual conformal field theories. Professor Wrase will investigate moduli stabilization in non-geometric string compactifications, including Landau-Ginzburg models, and the consistency of intersecting localized sources. He will also study scale-separated anti-de Sitter vacua, including new heterotic constructions, to determine when controlled lower-dimensional effective theories can arise from string theory. Professors Wrase and Cremonini will also develop string-theoretic models of accelerated expansion, improve the theoretical foundations and predictions of alpha-attractor inflation, explore cosmologies with and without event horizons, and determine how higher-derivative corrections affect moduli stabilization and the viability of de Sitter vacua and models of dynamical dark energy. Professor Cremonini will use holographic and effective-field-theory methods to develop more systematic descriptions of hydrodynamics and transport in strongly coupled matter, extending efficient methods for calculating viscosities and conductivities to systems with more general matter content, chemical potentials, magnetic fields, and finite-coupling effects. She will also study quantum corrections to near-extremal black holes and their consequences for transport, quantum chaos, information scrambling, and quantum-information-theoretic bounds. Together, these efforts will sharpen the criteria for consistent theories of quantum gravity, improve models that can be compared with cosmological observations, and identify general principles governing strongly coupled quantum matter and quantum information dynamics. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.