A Quantum Approach to Dark Matter

This work develops and explores a quantum-based theory which may enable the nature and origin of cold dark matter (CDM) to be understood without the need to introduce exotic particles. Despite the excellent successes of Lambda Cold Dark Matter (LCDM) cosmology on large scales, it continues to encounter several significant difficulties in its present form, particularly at the galactic cluster scale and below. In addition, crucial to LCDM theory is the existence of a stable weakly interacting massive particle (WIMP) which is yet to be detected. Using a quantum approach however, it is possible to predict the existence of certain macroscopic quantum structures that are WIMP-like even when occupied by traditional baryonic particles. These structures function as dark matter candidates for LCDM theory on large scales where it has been most successful, and retain the potential to yield observationally compliant predictions on galactic cluster and sub-cluster scales.Relatively pure, high angular momentum, eigenstate solutions obtained from Schrödinger's equation in weak gravity form the structural basis of this quantum approach. They are seen to have no classical analogue, and properties radically different to those of traditional localized matter (whose eigenstate spectra contain negligible quantities of such states). Salient features of some of the more tractable solutions include radiative lifetimes, which often far exceed the age of the universe, and energies and 'sizes' consistent with that expected for galactic halos. This facilitates the existence of sparsely populated structures with negligible electromagnetic emission and an inherent inability to undergo further coalescence or gravitational collapse.Viable structure formation scenarios can be constructed based on the seed potential wells of primordial black holes formed at the e+/e- phase transition. Composed of a plethora of relevant eigenstates, these structures potentially have suitable internadensity distributions and sufficient capacity to accommodate the required amount of dark matter. Additionally, eigenstate particles interact only negligibly with electromagnetic radiation and other baryonic particles. Traditional matter occupying such states will therefore be both invisible and weakly interacting with 'ordinary' particles, including macroscopic galactic objects. Structure formation, probably occurring before big bang nucleosynthesis (BBN), will introduce significant density inhomogeneity. If so, it should be possible to incorporate structures into universal evolutionary scenarios without significantly disturbing expected BBN ratios. The theory therefore provides a mechanism for dark matter to be primarily baryonic, without compromising the results of WMAP or the measurements of elemental BBN ratios.