Speaker
Tomás Codina
Date/Time
Date(s) - 06/05/2022
11:00 - 12:00
Location
IRIS Building, Room 1.221
At low energies, string theories are described by field theories, which include general relativity coupled to matter fields as a particular sector. Intriguingly, even classical string theory modifies general relativity in two important respects: it includes an infinite number of higher-derivative corrections governed by the (inverse) string tension α′, and it incorporates dualities, T-duality being a particular case. Even though the compatibility of string corrections with T-duality has been known for a long time already, the explicit form of these α′corrections is still an open problem.
Recently, however, a classification of these corrections to all orders in α′ was found by Hohm and Zwiebach for the particular case of 1-dimensional cosmological backgrounds by exploiting T-duality. The classification determines the full cosmological action up to some arbitrary coefficients that cannot be fixed by duality principles. In this talk I will present two methods that can be used to determine these coefficients: The first one consists of taking the higher- dimensional string low energy effective actions already present in the literature and performing a dimensional reduction to 1 dimension. For the second method, we consider the bosonic string theory in a cosmological background as our starting point and from there demand conformal invariance at the quantum level. I will present the results obtained so far by applying these two methods and discuss possible approaches to extend them to even higher orders.