PHI 115, March 2016
Written Assignment Mod 2
Answer the following:
What are the units of mass and the units of weight for the metric system?
What are the units of mass and the units of weight for the English system?
A. 9.8 N/Kg, m
Lab 1 Mod 1
Q 1 - Measure dimensions in an empty lot in a subdivion for a construction project
1. The accuracy limitations of the measuring device: For example a digital scale
may be accurate to 0.1 g, 0.01 g, 0.001 g, etc.,
The steps for the scientific method are listed in Chapter 1. List and explain each of the steps in the scientific
method in the context of the following situation. You do not have to resolve the question; just explain th
Topological insulator with time-reversal symmetry
Q: Can we get a topological insulator that preserves the time-reversal symmetry?
A: Yes, with the help of the spin degree of freedom.
7.1. spin-orbit coupling
In previous discussions, we i
Superconductivity and Higgs mechanism
Continuous symmetry breaking without Goldstone modes.
For some metal, if one reduces the temperature, the resistivity suddenly drops to zero at some critical temperature TC .
Topological insulators Part I: Phenomena
4.1. Quantum Hall effect
4.1.1. Hall effect
Consider electrons moving in a 2D plane (the system is known as a 2D electron gas or 2DEG). If we apply an in-plane electric field E, we
will get some el
6.1. tight-binding models
Tight-binding models are effective tools to describe the motion of electrons in solids. Here, we assume that the system is a discrete lattice and
electrons can only stay on the lattice site. T
Topological insulators Part II: Phase and gauge field
5.1. Some insulators have chiral edge states but others dont. Why?
A piece of plastic is an insulator. An IQH state is also an insulator. But they are clearly two different types of ins
Quantum field theory and Greens function
Condensed matter physics studies systems with large numbers of identical particles (e.g. electrons, phonons, photons) at finite temperature.
Quantum field theory arises naturally if we consider a quantum system
Linear Response Theory: The connection between
QFT and experiments
3.1. Basic concepts and ideas
Q: How do we measure the conductivity of a metal?
A: we first introduce a weak electric field E, and then measure the electric current J . In
Fermi liquid theory
2.1. Can we apply the free fermion approximation to a real metal?
Can we ignore interactions in a real metal? Experiments says yes (free fermion models work very well), but the theoretical answer is much
Magnets, 1D quantum system, and quantum Phase
In 1D, fermions can be mapped into bosons, and vice versa.
10.1. magnetization and frustrated magnets (in any dimensions)
Consider a lattice of spins. The Heisenberg model has the
Phase transition and spontaneous symmetry breaking
Q1: Symmetry: if a the Hamiltonian of a system has certain symmetry, can the system have a lower symmetry?
Q2: Analyticity: if we have only analytic functions, can we get