Unit:
Department of PhysicsLibrary of the School of Science
Author:
ΠΟΛΥΚΡΑΤΗΣ ΓΕΩΡΓΙΟΣ
Supervisors info:
Σπανός Βασίλειος, Αναπληρωτής Καθηγητής, Τμήμα Φυσικής ΕΚΠΑ
Original Title:
Αρχέγονα βαρυτικά κύματα από τον κοσμολογικό πληθωρισμό και CMB
Translated title:
Primordial gravitational waves from inflation and CMB
Summary:
In Chap. 0 we simply mention the most comonly used tools of General Relativity whose use wold be frequent in the rest of the analysis. We also show with simple steps that the Riemann tensor satisfies the wave equation, thus tells us that curvature waves is indeed a meaningfull concept. In the chapters of Part I, we deal with gravitational waves. In Chapter 1 in particular, we investigate the Einstein equations, moving though usefull gauges for the case of a linear perturbation of 1st order of the metric, and we get the equation of motion of this tensor perturbation (gravitational wave). We also investigate the effect that a gravitational wave has on a collection of free bodies and in particular the deformation of a ring of discrete bodies. In Chapter 2 we deal with the different kinds of gravitational wave signals and the running and future experiments for there detection. We also describe the of the nowadays most commonly used kind of gravitational wave detector, the interferometer. In Chapter 3 we deal with multipole terms ofgravitational radiation. In Capter 4 we write about the energy carried by the gravitational waves and we work on the so called small wave approximation, in order to find out their energy loss. In Chapter 5 we classify the different regions of the gravitational radiation spectrum and we mention the different experiments that specialize in each region. In the chapters of Part II we talk in general about the linear perturbations and their separation into scalar, vector and tensor parts , in an attempt to generalize the initial discussion of Chapter 1, in a zero curvature FRW universe. In the chapters of Part III we mention the theory of scalar field inflation and generalize the previous discussion of Part II both for tha case of one and more scalar fields, for the purpose of extracting the spectral power index. This discusion is important for the study of gravitational waves, since tensor perturbations contribute to this quantity. In Part IV we introduse the basic concepts and tools for the study of CMB. Finally in Part V we see how we can extract informations about the primordial perturbations of Part III, from CMB.
Main subject category:
Science
Keywords:
inflation, gravitational waves, perturbations, scalar perturbations, tensor perturbations, primordial perturbations, scalar field, scalar fields, General Relativity
