Dimensionsstabile

Dimensionsstabile is a term used in theoretical physics to describe a regime in which the effective dimensionality of spacetime and the sizes of extra spatial dimensions remain fixed over cosmological timescales. In theories with more than three spatial dimensions, the observed three-dimensional space expands while the additional dimensions are compactified at very small scales. Dimensionsstabile denotes a state in which the compact dimensions settle at constant radii and the number of large dimensions stays unchanged, so that low-energy physics remains effectively four-dimensional.

In most formulations, stability is realized when the moduli fields that describe the sizes and shapes of the extra dimensions sit at a potential minimum. This can result from background fluxes, curvature, brane tensions, and nonperturbative effects. In string theory, stabilizing these moduli is a central problem; frameworks such as flux compactifications and KKLT-type constructions aim to produce dimensionsstabile vacua with fixed extra-dimensional geometry and a controlled cosmological evolution.

Implications include the constancy of physical constants that depend on the geometry of extra dimensions and a predictable four-dimensional effective theory. Dimensionsstabile also influences cosmological evolution, shaping the expansion history and the onset of standard cosmology.

Limitations: achieving true global stability is challenging. Many models yield metastable or slowly evolving stabilization, and quantum corrections or finite-temperature effects can destabilize compact dimensions or reintroduce dynamics.

See also: moduli stabilization, flux compactification, KKLT, dimensional reduction, brane cosmology.