星系尺度上的玻色暗物质研究进展

星系尺度上的暗物质研究通常涉及各种不同的暗物质模型。在这些模型中,冷暗物质模型(CDM模型)受到了广泛关注。基于该理论模型的研究,可以较好地解释星系尺度和宇宙大尺度结构中的一些问题。然而,在研究星系小尺度结构时,存在一些该模型无法解释的观测现象。近年来,玻色-爱因斯坦凝聚暗物质模型(BEC-DM模型)和模糊暗物质模型(FDM模型)作为CDM模型的替代方案,受到了广泛关注和大量研究。在BEC-DM模型中,暗物质粒子被假设为一种处于宏观量子态的玻色子;而FDM模型则将暗物质描述为一个具有波动特性和极小质量的粒子。研究这两种理论模型有助于了解不同理论模型对星系中暗物质密度分布和相关性质的影响。在这一背景下,对星系尺度上的玻色暗物质理论模型及其粒子探测进行了简要概述。回顾了暗物质研究的历史,介绍了暗物质候选粒子及对其的探测方法。重点介绍了BEC-DM模型和FDM模型作为传统CDM模型的替代方案,并探讨了它们在解决问题方面的优势。

Single Parameter Model for Cosmic Scale Photon Redshift in a Closed Universe

A successful single parameter model has been formulated to match the observations of photons from type 1a supernovae which were previously used to corroborate the standard 𝛬 cold dark matter model. The new single parameter model extrapolates all the way back to the cosmic background radiation (CMB) without requiring a separate model to describe inflation of the space dimensions after the Big Bang. This single parameter model assumes that spacetime forms a finite symmetrical manifold with positive curvature. For the spacetime manifold to be finite, the time dimension must also have positive curvature. This model was formulated to consider whether the curvature of the time dimension may be related to the curvature of the space dimensions. This possibility is not considered in the more complex models previously used to fit the available redshift data. The geometry for the finite spacetime manifold was selected to be compatible with the Friedmann equation with positive curvature. The manifold shape was motivated by an assumption that there exists a matter hemisphere (when considering time together with a single space dimension) and an antimatter hemisphere to give a symmetrical and spherical overall spacetime manifold. Hence, the space dimension expands from a pole to the equator, at a maximum value for the time dimension. This is analogous to the expansion of a circle of latitude on a globe from a pole to the equator. The three space dimensions are identical so that any arbitrary single space direction may be selected. The initial intention was to modify the assumed geometry for the spacetime manifold to account for the presence of matter. It was surprisingly found that, within the error of the reported measurements, no further modification was necessary to fit the data. The Friedmann equation reduces to the Schwarzschild equation at the equator so this can be used to predict the total amount of mass in the Universe. The resulting prediction is of the order of 1051 kg. The corresponding density of matter at the current time is approximately 1.6 × 10-28 kg·m-3.

开宇宙的XCDM模型

用XCDM模型探讨开宇宙的情形.结果表明,当考虑宇宙加速膨胀的事实后,该模型下的冷暗物质(CDM)场将具有从负能正压状态向正能负压状态演化这一怪异的特点.