Naomi Gendler

Research

The four-dimensional physics resulting from geometric compactifications of string theory is largely determined by the shape and size of the underlying compactification manifold. I try to understand what the generic features of these effective theories are, and to compare them to experiments and observations concerning particle physics and cosmology.

The string theory axiverse

One of the most universal features of string compactifications is the existence of a number of axions: light scalar fields with approximate shift symmetries. Axions were proposed independently of string theory, in order to solve the strong CP problem, but they are also excellent candidates to explain dark matter, dark energy, or inflation. I study axions in string compactifications, computing their properties in a large ensemble of type IIB Calabi–Yau compactifications.

Key papers

Quantum gravity constraints

Not every effective field theory can be realized as a UV complete theory of quantum gravity. Several criteria have been proposed to distinguish these EFTs, but two central proposals are the Weak Gravity Conjecture and the Distance Conjecture. I check these proposals in various forms in explicit geometries, trying to understand what can be proven or shown mathematically.

Key papers

The geometry of Calabi–Yau manifolds

Underlying any four-dimensional effective theory coming from string theory is the geometry of the compactification manifold. Therefore, understanding these geometries is crucial for doing phenomenology. I have studied this from several angles—which cycles are holomorphic vs. non-holomorphic, how many topologically distinct Calabi–Yau threefolds there are, and which four-cycles can host instantons that actually correct the effective theories.

Key papers

A complete list is on the publications page.