Ultimately, every question in cosmology leads back to the question of initial conditions. Classical physics, even in the context of an inflationary phase, cannot address this question – this is the domain of quantum cosmology. The best known theories of initial conditions are the no-boundary and tunnelling proposals. Both were formulated somewhat heuristically, in the path integral approach to quantising gravity. And due to a lack of adequate means, progress has been relatively modest in this subject.
Qosmology will apply new mathematical methods, based on Picard-Lefschetz theory, to define gravitational path integrals rigorously for the first time. Generalised theoretical concepts, in particular tunnelling in complex time, will lead to new types of solutions describing quantum transitions between contracting and expanding universes, effectively providing quantum resolutions of the big bang. These solutions will not only extend the scope of the existing theories of initial conditions, but may suggest entirely novel approaches. In addition Qosmology will continuously improve existing numerical methods, allowing for extensive studies of the big-bang-resolving solutions as well as of quantum tunnelling effects generally.
Moving beyond a description of the background, the fluctuations in the universe and an observational verification of their quantum origin are of fundamental interest. Are there remnants of quantum correlations in the distribution of galaxies in our universe? Qosmology will forge new paths by exploring quantum gravitational effects, exploiting novel measures of quantumness, and focussing on the interconnectedness between background and fluctuations, dynamics and initial conditions.
Qosmology will, for the first time since the 1980s, reach a significant advance in our understanding of quantum theory applied to the universe as a whole.
Fields of science
Funding SchemeERC-COG - Consolidator Grant
See on map