A cosmological field theory

Cosmological tachyon from cubic string field theory

The classical dynamics of the tachyon scalar field of cubic string field theory is considered on a cosmological background. Starting from a nonlocal action with arbitrary tachyon potential, which encodes the bosonic and several supersymmetric cases, we study the equations of motion in the Hamilton–Jacobi formalism and with a generalized Friedmann equation, appliable in braneworld or modified gr...

Field theory models for variable cosmological constant

Anthropic solutions to the cosmological constant problem require seemingly unnatural scalar field potentials with a very small slope or domain walls (branes) with a very small coupling to a four-form field. Here we introduce a class of models in which the smallness of the corresponding parameters can be attributed to a spontaneously broken discrete symmetry. We also demonstrate the equivalence ...

3) The Cosmological Constant in Classical and Quantum Field Theory

Various contributions to the cosmological constant are discussed and confronted with its recent measurement. We briefly review different scenarious – and their difficulties – for a solution of the cosmological constant problem.

Perturbation Theory of the Cosmological Log-Density Field

Effective Field Theory, Black Holes, and the Cosmological Constant

Bekenstein’s proposed bound on the total entropy of any system in a volume L3, S ≤ SBH ≡ πM 2 PL 2, suggests a radical breakdown of quantum field theory in large volume. Given the success of quantum field theory for describing particle physics, we conjecture a relationship between UV and IR cutoffs for which an effective field theory without quantum gravity should be a good description of Natur...