利用星系旋转曲线及行星近日点异常进动对弦理论中规范场限制的研究

发布时间：2018-12-11 21:54

【摘要】：在本工作中我们主要讨论一个由弦理论启发而来、可用于天文和宇宙学的(唯像)模型。在该模型中物质通过与弦理论中的规范场耦合而受到额外的一个作用力,该作用力在一些宇宙学或者天文学现象及观察结果中可能会有所表现。我们首先从弦理论出发简单介绍该模型,然后将其应用于多个宇宙学或天文学现象的解释,涉及到的问题和现象包括星系旋转曲线问题以及太阳系中某些行星近日点的异常进动现象。在星系旋转曲线问题方面,我们选取了总共二十二个星系的旋转曲线数据,利用该弦理论模型对这些曲线进行了拟合。作为比较,我们还利用一个简单的暗物质模型对同一组数据进行了拟合。根据拟合结果,该弦理论模型与该暗物质模型在这一数据源上显示出了相近的拟合能力。弦理论中的规范场强度是作为该弦理论模型中一个拟合参数的,根据这二十二个星系曲线数据的拟合,其在该组星系中的强度覆盖大约两个数量级。通过量纲分析我们还可以从该弦理论模型得出一个关于规范场强度,星系(大小)尺度以及星系总亮度之间的方程。我们利用这二十二个星系的数据以及弦理论模型对其拟合所得的结果对该方程进行了验证。我们尝试利用该模型来解释最近发现的太阳系中某些行星近日点的异常进动现象。在此之前,我们首先进行了关于行星在受到微扰情况下近日点进动的理论分析,成功解决了以下两种情形下的一般进动问题：一、微扰为类磁场力；二、微扰为一般的幂次中心力。对第二种情形,我们还得到了一个判断该微扰导致正向进动还是反向进动的简单规则。我们随后将该模型应用于最近观察到的太阳系中某些行星近日点的异常进动,假设是该模型中的额外(类磁)力造成了此异常进动,利用之前得到的关于进动的理论工具,我们计算了在太阳系中几个行星所处位置上的规范场强度。根据场强度在各处的大小情况,我们接着对强度分布进行了一个带预设强度形式的拟合,该预设形式中太阳系中的场为两个分量的叠加：其一为太阳所产生的类偶极矩场,其二为银河系中其他物质所产生的常数背景场。作为比较,我们还利用了银河系旋转曲线来估计了银河系中的场强度,所得的强度与进动所得的处在类似的数量级上。
[Abstract]:In this work we mainly discuss a phenomenological model inspired by string theory which can be used in astronomy and cosmology. In this model, the matter is subjected to an additional force by coupling with the gauge field in string theory, which may be shown in some cosmological or astronomical phenomena and observations. We first introduce the model briefly from string theory, and then apply it to the interpretation of multiple cosmological or astronomical phenomena. The problems and phenomena involved include the rotation curve of galaxies and the anomalous precession of the perihelion of some planets in the solar system. In terms of the rotation curves of galaxies, we select the rotation curve data of 22 galaxies and use the string theory model to fit these curves. For comparison, a simple dark matter model is used to fit the same set of data. According to the fitting results, the string theory model and the dark matter model show similar fitting ability on this data source. The intensity of gauge field in string theory is used as a fitting parameter in the string theory model. According to the fitting of the curve data of 22 galaxies, the intensity of the gauge field in this group of galaxies covers about two orders of magnitude. Through dimensional analysis, we can also derive an equation from the string theory model about the intensity of the gauge field, the scale of the galaxy (size) and the total brightness of the galaxy. The equation is verified by using the data of 22 galaxies and the string theory model. We try to use this model to explain the anomalous precession of the perihelion of some planets in our solar system. Before this, we analyze the perihelion precession of the planet in the case of perturbation, and successfully solve the general precession problem in the following two cases: first, the perturbation is magnetic field force; Second, the perturbation is a general power center force. For the second case, we also obtain a simple rule to determine whether the perturbation leads to forward precession or reverse precession. We then apply the model to the recently observed anomalous precession of the perihelion of some planets in the solar system, assuming that the extra (magnetoid) force in the model caused the anomalous precession, using previously available theoretical tools on precession. We have calculated the intensity of the gauge field at the position of several planets in the solar system. According to the magnitude of the field intensity everywhere, we then fit the intensity distribution with a preset intensity form, in which the field in the solar system is superimposed by two components: one is the dipole like moment field produced by the sun. The other is the constant background field produced by other matter in the Milky way. As a comparison, we also estimate the field intensity in the Milky way by using the galactic rotation curve, which is in a similar order of magnitude to that obtained by the precession.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：P15

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