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所在平台: Udemy |
课程主页: https://www.udemy.com/course/quantum-gravity-from-gravitational-waves-to-gravitons/
课程评论：没有评论
课程名称：量子引力：从引力波到引力子 课程概述： 本课程探讨了在弱引力场条件下，如何利用量子场论的方法对引力进行量子化。课程将从爱因斯坦场方程出发，假设度规张量是平直时空的一种小扰动，并推导出二阶扰动下的爱因斯坦场方程。从中，我们将看到引力子（质量为零的自旋2场）是如何自然涌现的。 学习路径： 1. **引力场方程的扰动分析**：从广义相对论的爱因斯坦场方程出发，对度规张量进行小扰动，推导出二阶扰动方程。 2. **引力子的概念**：理解扰动方程如何揭示引力子作为一种质量为零的自旋2场的性质。 3. **理论的量子化**：将经典理论过渡到量子领域，通过路径积分和配分函数的概念对引力场进行量子化。 4. **量子效应的理解**：学习如何推导出引力子的平均数量，以及理解引力波的极化概念。 先修要求： 本课程面向已熟悉张量微积分、爱因斯坦场方程、路径积分语言的量子场论以及复分析的学生。 面向人群： 对引力量子化、早期宇宙和黑洞物理学有浓厚兴趣，并具备扎实的物理学理论基础的进阶学生。
The particles we encounter in nature, whether massive or massless, experience the gravitational interaction due to their energy content. Although gravitational interactions are way smaller than other interactions in nature, the incorporation of gravity in quantum interactions seems important (for example in the description of our early universe or black hole physics).You might hear people addressing the incompatibility between quantum physics and general relativity, as well as the need to make efforts in order to find the desired theory of Quantum Gravity.Sometimes you might hear people refer to String Theory, some other times to Loop Quantum Gravity. These theories have opened up new ways of looking at reality, for sure, but we might still be a long way from being able to test them.On the other hand, under certain circumstances, it is already possible to quantize gravity, by using the well-known quantum field theory approach. This is possible only when we are dealing with weak gravitational fields.In this course, we will see how the concept of graviton emerges quite naturally by considering small deviations of the metric tensor from flat spacetime.In particular, we will start from Einstein field equations of General Relativity, and we will assume that the metric tensor is a small perturbation of the Minkowski metric.From there, we will derive Einstein field equations up to second order of the perturbation.We will see that the equations derived in this way are those of a massless spin-2 field.After that, we proceed to solve the equations and find a way to express the metric tensor.After dealing with the classical equations, we switch to the quantum realm by quantizing the field, recalling the concept of path integral and partition function. The quantum theory will allow us to derive the average number of gravitons and understand the concept of polarization of gravitational waves.In all the derivations it is assumed that the student is familiar with tensor calculus, Einstein field equations, quantum field theory in the language of path integrals, complex calculus. Therefore, it goes without saying that the course is aimed at students who master these concepts. On the other hand, the equations will be derived step by step, leaving the time to digest the concepts.
