What are the basic degrees of freedom and interactions underlying gravitational and particle physics? What is the mechanism behind the initial seeds of structure in the universe, and how can we test it using cosmological observations? Is there a holographic framework for cosmology that applies throughout the history of the universe, accounting for the effects of horizons and singularities? What new phenomena arise in quantum field theory in generic conditions such as finite density, temperature, or in time dependent backgrounds?Professor Silverstein attacks basic problems in several areas of theoretical physics. She develops concrete and testable mechanisms for cosmic inflation, accounting for its sensitivity to very high energy physics. This has led to a fruitful interface with cosmic microwave background research, contributing to a more systematic analysis of its observable phenomenology.Professor Silverstein also develops mechanisms for breaking supersymmetry and for stabilizing the extra dimensions of string theory to model the immense hierarchies between the cosmological horizon, electroweak, and Planck scales in nature. In addition, Professor Silverstein uses the ultraviolet completion of gravity afforded by string theory to address questions of quantum gravity, such as singularity resolution and the physics of black hole and cosmological horizons. Professor Silverstein also uses modern techniques in quantum field theory to model strongly coupled phenomena motivated by measurements in condensed matter physics.Areas of focus:- UV complete mechanisms and systematics of cosmic inflation, including string-theoretic versions of large-field inflation (with gravity wave CMB signatures) and novel mechanisms involving inflaton interactions (with non-Gaussian signatures in the CMB)-Systematic theory and analysis of primordial Non-Gaussianity, taking into account strongly non-linear effects in quantum field theory encoded in multi-point correlation functions -Long-range interactions in string theory and implications for black hole physics- Concrete holographic models of de Sitter expansion in string theory, aimed at upgrading the AdS/CFT correspondence to cosmology- Mechanisms for non-Fermi liquid transport and $2k_F$ singularities from strongly coupled finite density quantum field theory- Mechanisms by which the extra degrees of freedom in string theory induce transitions and duality symmetries between spaces of different topology and dimensionality