Following the recent results announced by DESI, the interest in quintessence models may increase dramatically. So, this is a good time to write a small post on the basic ideas behind quintessence. Basics of GR and QFT are assumed for this post.
1/31
#physics #scicomm Firstly, let’s review the basic idea of a cosmological constant. The Einstein equation without a cosmological constant is still a consistent equation.
2/31
#physics #scicomm

This is a post to describe how we construct the standard model lagrangian and generate the masses for gauge bosons and fermions. I will assume basic familiarity with QFT, lagrangians, gauge transformations, and gauge groups (like U(1), and SU(2)).
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#physics #scicomm Recall that the mass term of a scalar field φ is simply proportional to φ2. Vector fields have similar mass terms. For fermions, the mass term is written in terms of their left handed part and right handed part. All of these forms are given in the picture below.
2/65
#physics

In this post, we will go through the reasoning that gives us the Schwarzchild solution of Einstein field equations. Prerequisites for this post include familiarity with Einstein field equations.
1/23
#physics #scicomm We start with the Einstein field equation (EFE) and convert it to a form that is used to solve this equation. This form is called the trace reversed form and to derive it, we contract EFE with the metric tensor.
2/23
#physics #scicomm

In this small thread, I will show why the first few possible corrections to the Einstein-Hilbert action are the way they are. Basic familiarity with General Relativity is assumed. 🧵
1/31
#physics #scicomm I will use the natural units (units used in high-energy physics) in this article. In these units, the unit of length is the inverse of the unit of energy (i.e. [Length]=[Energy]^(-1)).
2/31
#physics #scicomm

This is a long thread for a chapter-by-chapter review and a reading guide for volume 1 of Polchinski’s book on string theory. Familiarity with the basics of QFT and GR is required (you will need these pre-requisites to read the book anyway)
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#physics #scicomm A guide to this review

This is a review and a reading guide for Polchinski’s first volume. Polchinski’s two volumes on string theory are still considered to be the best and most comprehensive resources to learn string theory.
2/69
#physics #scicomm

This post summarizes the reasoning that goes into deriving Einstein’s field equation. There is more than one way to derive this field equation but I will focus on the most conventional path to derive it. 1/28
#Physics #scicomm For this post, a basic understanding of tensor analysis and special relativity is assumed to understand this post. 2/28
#Physics #scicomm

This is a post about the generalization of the concept of global symmetries. This area has been a very active area of research for the last 8 years or so. 1/28
#Physics #scicomm #research A basic understanding of global symmetries unitary operators (acting on quantum states and operators) and local operators is required to read this post. This topic may look esoteric but it has applications in well-known theories of physics, including the standard model. 2/28

This is a brief post about nongeometric backgrounds in string theory. We will define these terms precisely in the following but naively, these can be thought of as "spaces" on which a string moves that don't have a "geometric" interpretation. 1/n
#Physics #scicomm A basic understanding of field theory is required. I'll try to make it as accessible as I can (without distorting the results).
In QFT, the word "background" usually means a set of fields that are present in the theory but whose dynamics aren't part of the theory. 2/n

Let's do a small thread on D-Branes and their charges. Before starting, let's review some familiar concepts so that it is easy to understand what follows. 1/13
#Physics #SciComm #Dbrane #strings #research In electrodynamics (using Newtonian space and time) the magnetic field is represented by a vector potential A. In order to describe the electric field, we need another scalar quantity called the scalar potential. 2/13