Related papers: Cosmological Constant Seesaw in String/M-Theory
In this paper we model the transition from the non-geometric holographic cosmology regime, to the usual radiation dominated (RD) cosmology, known as reheating in the case of (perturbative) inflation. We find that we can easily transition…
A mechanism for suppressing the cosmological constant is developed, based on an analogy with a superconducting phaseshift in which free fermions coupled perturbatively to a weak gravitational field are in an unstable false vacuum state. The…
We examine to what extent perturbative alpha'-corrections can generate a small cosmological constant in warped string compactifications. Focusing on the heterotic string at lowest order in the string loop expansion, we show that, for a…
According to the "dark dimension" (DD) scenario, we might live in a universe with a single compact extra dimension, whose mesoscopic size is dictated by the measured value of the cosmological constant. This scenario is based on swampland…
We consider, in five dimensions, the effective action from heterotic string which includes quantum gravity corrections up to (a')^2. The expansion, in the string frame, is in terms of |a'R|, where R is the scalar curvature and uses the…
Asymptotic (late-time) cosmology depends on the asymptotic (infinite-distance) limits of scalar field space in string theory. Such limits feature an exponentially decaying potential $V \sim \exp(- c \phi)$ with corresponding Hubble scale $H…
Efforts to understand the origin of the cosmological constant {\Lambda} and its observed value have led to consider it as a dynamical field rather than as a universal constant. Then the possibility arises that the universe, or regions of…
The harmonic oscillator in pseudo euclidean space is studied. A straightforward procedure reveals that although such a system may have negative energy, it is stable. In the quantized theory the vacuum state has to be suitably defined and…
We study a cosmic string solution of an N=1-supersymmetric version of the Cremmer-Scherk-Kalb-Ramond (CSKR) Lagrangian coupled to a vector superfield by means of a topological mass term. The 2-form gauge potential is proposed to couple…
We study a Newtonian cosmological model in the context of a noncommutative space. It is shown that the trajectories of a test particle undergo modifications such that it no longer satisfies the cosmological principle. For the case of a…
An approach that allows studying the relationship between the neutralization of the cosmological constant and instantons for cosmology coupled to antisymmetric fields is proposed. Using suitable variables, the Lagrangian leading to the FRW…
We study the relationship between static p-brane solitons and cosmological solutions of string theory or M-theory. We discuss two different ways in which extremal p-branes can be generalised to non-extremal ones, and show how wide classes…
Recent observations of Type 1a supernovae indicating an accelerating universe have once more drawn attention to the possible existence, at the present epoch, of a small positive Lambda-term (cosmological constant). In this paper we review…
Orbifold branes in string theory are investigated, and the general field equations on the branes are given explicitly for type II and heterotic string. It is shown that the effective cosmological constant on each of the two branes can be…
We review a solution of the cosmological constant problem in a brane-world model with infinite-volume extra dimensions. The solution is based on a nonlinear generally covariant theory of a metastable graviton that leads to a large-distance…
The implications of string theory for understanding the dimension of uncompactified spacetime are investigated. Using recent ideas in string cosmology, a new model is proposed to explain why three spatial dimensions grew large. Unlike the…
It has long been known that strings wound around incontractible cycles can play a vital role in cosmology. In particular, in a spacetime with toroidal spatial hypersurfaces, the dynamics of the winding modes may help yield three large…
We show that if there is a realistic 4-d string, the dilaton and moduli supermultiplets will generically acquire a small mass O(m_{3/2}), providing the only vacuum-independent evidence of low-energy physics in string theory beyond the…
The converging mechanism discussed in [Damour & Nordtvedt, Physical Review Letters,70,15] for scalar-tensor theories has been applied to dilaton-like theories in several subsequent papers. In the present communication, we show that an…
We determine the most general form of the antisymmetric $H$-field tensor derived from a purely time-dependent potential that is admitted by all possible spatially homogeneous cosmological models in 3+1-dimensional low-energy bosonic string…