This page contains my personal notes prepared while studying Polchinski’s String Theory Vol-1. The notes follow the structure of the textbook and include detailed derivations, explanations, and supplementary calculations. I have taken some help from “A Companion Reader to Polchinski String Theory by Stany M. Schrans”.

Chapter 1 — A first look at strings

• 📄 Introduction and the Relativistic Particle

• 📄 Actions for Classical Relativistic Strings

• 📄 Open String Spectrum

• 📄 Closed and Unoriented Strings

Chapter 2 — Worldsheet Conformal Field Theory

• 📄 Massless Scalar Field in Euclidean Two-Dimensional Worldsheet

• 📄 Operator Product Expansion

• 📄 Noether’s Theorem and Ward Identity

• 📄 Conformal Transformations and Invariance

• 📄 Free Conformal Field Theories

• 📄 The Virasoro Algebra

• 📄 Mode Expansions for Scalar (X^\mu) and (bc) CFT

• 📄 Vertex Operators and State–Operator Correspondence

• 📄 State–Operator Correspondence for Scalar (X^\mu) and (bc) CFT

Chapter 3 — The Polyakov path integral

• 📄 Sums Over World-Sheets

• 📄 Couplings and Topological Terms in the Polyakov Action

• 📄 Gauge Fixing and the Faddeev–Popov Determinant

• 📄 Weyl Anomaly

• 📄 Scattering Amplitudes

• 📄 Vertex Operators and Strings in Flat Spacetime

• 📄 Strings in Curved Spacetime

Chapter 4 — The string spectrum

• 📄 Old Covariant Quantization (OCQ)

• 📄 BRST Quantization

• 📄 BRST Quantization of the String

• 📄 BRST No Ghost Theorem