Statistical Physics

This is a set of lecture notes for statistical physics.


I have finally finished this whole set of notes for my statistical mechanics class. It was an excellent course thought by Professor V. M. Kenkre in 2014.

Professor Kenkre’s lectures are fantastic. They were like inspiring and exciting thrilling movies. I am very grateful to him for this adventure of modern statistical mechanics.

Professor Kenkre’s lectures have such a power that a tiny hint would develop into an important result as the adventure goes on. The only words I can think of for the lectures are the words used on the best chinese novel, Dream of the Red Chamber.


It says that the subplot permeates through thousands of pages before people realize it’s importance.

I am also very grateful to the TA of this course, Anastasia, who helped me a lot with my homework and lecture notes.


Statistical Physics is one of the holy grail of physics. It taught us great lessons about our universe and it is definitely going to teach us more. Some ideas (such as Verlinde’s scenario) even put thermodynamics and statistical physics as the fundamental theory of all theories which leads to the thought that everything is emergent has been announced.

In simple words, statistical mechanics is the mechanics of large bodies.

  • Classical Mechanics is Newton’s plan of kinematics.
  • Large number of bodies means a lot of degrees of freedom (DoFs). The system is large if the DoFs add up to \(10^{23}\). That being said, we would study matter consisting particles of the order Avogadro’s number.
  • Bodies, of course, is the subject or system that we are dealing with.

One interesting question about statistical mechanics is how we end up with probabilities.

We wouldn’t need probability theory if we carry out Newton’s plan exactly. Note that the first thing we compromise to come over the obstacles is to drop the initial conditions of the particles since it’s impossible to write down all the initial conditions of a large number of particles. In order to describe the system of particles, we have to use probability on the particles. We will also see that some dynamics of the particles have to be dropped to make statistical quantities calculable. This is another reason that we need probabilities.

It’s kind of disappointing that Newton’s plan didn’t succeed.

The sitemap of the website can be downloaded from: sitemap.xml or sitemap.xml.gz .

Some Topics in Statistical Mechanics


This open source project is hosted on GitHub: Statistical Physics .

Read online: Statistical Physics Notes .

Download the Latest PDF Version .

Many thanks to open source project Sphinx for it saves me a lot of time on making this website.

RST cheat sheet from ralsina .

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© Copyright 2017, Lei Ma. | On GitHub | Index of Statistical Mechanics | Created with Sphinx1.2b2.