One-loop bosonic string and De Sitter space

Sabine Harribey (1, 2) , Dimitrios Tsimpis (3)

1 CPHT - Centre de Physique Théorique [Palaiseau]
2 ENS de Lyon - École normale supérieure de Lyon
3 IPNL - Institut de Physique Nucléaire de Lyon

We calculate the bosonic string one-loop three- and four-point amplitudes to quadradic order in momentum, and we read off the one-loop low-energy two-derivative effective action for the massless fields, Seff . Treating the renormalized one-loop vacuum energy as a tunable parameter and extrapolating to a supercritical dimension D>26 , one can reach a regime where the one-loop couplings in Seff are of the same order as the tree-level ones while all higher-loop corrections are negligible. Moreover the effective spacetime curvature is small in string units. We show that the effective action thus obtained admits weakly-curved de Sitter solutions with constant dilaton at small string coupling.

Mots clés: string model: boson; string: coupling; space: de Sitter; vacuum state: energy; effective action; tree approximation; space-time; curvature; dilaton

Domaines: Physique des Hautes Energies - Théorie [hep-th]; Relativité Générale et Cosmologie Quantique [gr-qc]

Sabine Harribey, Dimitrios Tsimpis. One-loop bosonic string and De Sitter space. Nucl.Phys.B, 2019, 948, pp.114768. ⟨10.1016/j.nuclphysb.2019.114768⟩. ⟨hal-01897220⟩