Tuesday, January 29, 2019

Why is condensed matter physics important and interesting?

I am trying to get some momentum in writing A Very Short Introduction to Condensed Matter Physics. The intended audience is the intellectually curious person with little background in science. My goal is to convince them that CMP is important and interesting. I can think of several reasons.

1. CMP is intimately connected with everyday technology ranging from liquid crystal displays to computer chips.
2. CMP comprises the majority of physics (employees, papers, conferences, ...) and has significant interaction with areas of science and engineering.
3. CMP is a rich source of creative ideas, concepts, and techniques that represent a significant intellectual achievement and are relevant to many other intellectual endeavors.
4. CMP is full of surprises. We keep discovering new unanticipated phases of matter.
5. CMP presents significant scientific challenges: theoretical, computational, and experimental (from characterisation to sample synthesis).

I am going to focus on 3.
However, it is interesting that the traditional route is 1. Furthermore, different people (including reviewers of the book proposal) are quite divided about 1. versus 3.
[More on that later following this article].

What are the big picture ideas of condensed matter, that are significant intellectual achievements in their own right and particularly relevant to other endeavors?
Here are a few suggestions. It provides very concrete systems to address, at both the mathematical and experimental level, the following issues, which turn out to be often inter-related.

A. Qualitative distinctions are defined by discontinuities. (Different phases of matter).

B. Simple models of complex systems. (Landau theory of phase transitions; Effective Hamiltonians).

C. Universality versus particularity. (Universality classes for critical phenomena).

D. Emergence and the hierarchal nature of reality. (Effective interactions. Renormalisation.)

What do you think are the great intellectual achievements of condensed matter that people need to know about?

1 comment:

  1. E. The concept of a quasiparticle and that elementary excitations may involve complex combinations of the variables in the original system

    F. The roles of symmetry and topology, e.g. liquid crystal systems

    G. What Anderson calls 'generalized rigidity"

    [Most/all of this may already be included in some form in the points you've listed above]