Theory HEP Seminar

Cosmological Perturbations in Double Field Theory

Allison Pinto

Humbolt University

String theory is a candidate theory of quantum gravity, yet no experimental evidence has been observed. However, more precise cosmological measurements in the future may allow for revealing quantum gravitational effects and thus it is desirable to find ways to test string theory in the context of cosmology.

Double field theory, a manifestly T-duality invariant theory describing the momentum and winding modes of the string, may offer an additional approach for computing stringy observables. In this talk I would like to share some recent results from joint work with Olaf Hohm on cosmological perturbations in double field theory. We expand double field theory around time-dependent backgrounds to quadratic and cubic order. We identify gauge invariant linear perturbations and express the quadratic action in terms of these, establishing a starting point for future computations such as correlation functions.