[论文解读] Variations of constants as a test of gravity, cosmology and unified models

V. N. Melnikov|ArXiv.org|Oct 19, 2009

Cosmology and Gravitation Theories参考文献 63被引用 8

一句话总结

该论文提出SEE空间任务及实验室扭力平衡实验，以检验引力常数G的变化，包括其时间导数ḊG和空间依赖性G(r)。通过精确的轨道动力学与灵敏的力探测，SEE有望将G的测量精度提升3–4个数量级，而实验室实验则在0.1米至10⁷米范围内探测Yukawa型偏离，耦合强度α的灵敏度达到10⁻¹⁰水平。

ABSTRACT

Gravitation as a fundamental interaction that governs all phenomena at large and very small scales, but still not well understood at a quantum level, is a cardinal missing link in unification of all physical interactions. Discovery of the present acceleration of the Universe, the dark matter and dark energy problems are also a great challenge to modern physics, which may lead to a new revolution in it. Integrable multidimensional models of gravitation and cosmology make up one of the proper approaches to studying basic issues and strong field objects, the early and present Universe and black hole (BH) physics in particular. Our main results within this approach are described for both cosmology and BH physics. Problems of the absolute G measurements and its possible time and range variations are reflections of the unification problem. The choice, nature, classification and precision of determination of the fundamental physical constants as well as their role in a transition, expected in 2011, to new definitions of the main SI units, supposed to be based on fundamental physical constants and stable quantum phenomena, are described. The problem of temporal variations of constants is also discussed, temporal and spatial variations of G in particular. A need for further absolute measurements of G, its possible range and time variations is pointed out. The multipurpose space project SEE is briefly described, aimed at measuring G and its stability in space and time, with precision 3-4 orders better than at present. It may answer many important questions posed by gravitation, cosmology and unified theories. A project of a laboratory experiment for testing possible deviations from the Newton law is also presented.

研究动机与目标

• 为以前所未有的精度和稳定性解决测量引力常数G的未解难题。
• 检验G的时间与空间变化，包括其时间导数ḊG和范围依赖性G(r)，作为统一引力与宇宙学模型的探针。
• 开发基于空间与地面的实验，检验广义相对论之外的基础物理，包括对平方反比定律的偏离。
• 通过改进绝对G测量，支持基于基本常数的SI单位重新定义。
• 探讨G变化对统一理论、量子引力及包含暗能量或常数变化的宇宙学模型的影响。

提出的方法

• 设计SEE（卫星能量交换）任务，采用三体系统：地球、无拖曳卫星及处于独特马蹄形轨道上的测试质量，以隔离引力效应。
• 建立最优轨道模型（圆形、椭圆轨道，含地球四极矩修正），以最大化对G及Yukawa型相互作用的敏感度。
• 计算测试质量的径向、纵向与横向振荡、非球形形状及高能粒子导致的带电效应的误差预算。
• 利用旋转球壳中偏移的空腔产生周期性扭矩，作用于扭力平衡系统，通过谐波分析检测非引力力。
• 应用谱分析检测周期信号的一次谐波，显著增强对Yukawa型相互作用的敏感度。
• 基于制造公差与实验室实验中的热涨落，评估灵敏度极限。

实验结果

研究问题

• RQ1 引力常数G是否随时间或空间变化，其变化的极限是什么？
• RQ2 利用空间任务与实验室实验，检测引力平方反比定律偏离的最大灵敏度可达多少？
• RQ3 与当前地面实验相比，SEE任务在提升G、ḊG与G(r)测量精度方面能实现多大程度的改进？
• RQ4 实验室扭力平衡实验在米尺度至行星尺度范围内，能多大程度探测到具有Yukawa型势的新力？
• RQ5 轨道动力学与扰动（如地球四极矩）如何影响空间实验中G的测量？

主要发现

• SEE任务预计可将G、其时间导数ḊG及空间依赖性G(r)的测量精度提升3–4个数量级，优于当前测量水平。
• 实验室扭力平衡实验在0.1米至10⁷米的相互作用范围中，对Yukawa耦合强度α的灵敏度达到约10⁻¹⁰。
• 已确定SEE的最优轨道，包括1500公里、3000公里及500公里（国际空间站自由飞行器配置）高度的圆形与低偏心率椭圆轨道，对扰动具有最小敏感度。
• 误差预算分析表明，测试质量舱的径向与横向振荡、导引体的非球形度及带电效应均可控制在允许公差范围内。
• 实验室实验中周期信号的一次谐波为检测非引力力的最优选择，显著提升信噪比性能。
• 本研究证实，SEE与实验室实验均为检验统一引力模型、替代引力理论及基本常数稳定性的可行工具。