Monthly Archives: February 2025
Weakly Coupled Quantum Field Theories
Problem #\(1\): Write down a general \(\phi\)-dependent perturbation to the Klein-Gordon Lagrangian density \(\mathcal L\) for a real scalar field \(\phi\), and explain why in practice only the first \(2\) terms of such a perturbation need to be considered. Solution … Continue reading
Toric Code
The purpose of this post is to explain what the toric code is, and its potential use as a fault-tolerant quantum error correcting stabilizer surface code for topological quantum computing. To begin, consider an \(N\times N\) square lattice \(\Lambda\) with … Continue reading
The IR Spectrum of \(\text{C}_{60}\)
The purpose of this post is to explain why, experimentally, one only observes \(4\) electric dipole transitions in the IR spectrum of buckminsterfullerene, also known as \(\text C_{60}\) or informally as the buckyball: Buckyball Basics The simplest conceptual way to … Continue reading