Landau and Lifshitz Electrodynamics reading group

Jeff Cina 19 June 2009

First meeting: 12:30 PM Friday 18 June 1999 in 151 Klamath Hall (which is now Mike

Kellman’s office).

Concluding meeting 9 AM Monday June 2009 in 139 Klamath Hall (Cina lab). Xiaolu

Cheng presenting, Jason Biggs, Craig Chapman, Jeff Cina, present; Mary Rohrdanz and

Jason Ellis participating via iChat.

Original attendees: Mary Rohrdanz,* Travis Humble, Yu-Chen Shen, Vivian Tyng, Mark

Watry, Jeff Cina, and several others.

Other regular participants: Aniruddha Chakraborty, Yanling Zhao, Chao Li, Megan

Tvedt, Craig Chapman, Jason Biggs, Xiaolu Cheng, Chris Williams,* Jason Ellis.*

*Joined in at least some of the time via iChat.

Over the course of 10 years, meeting weekly (during one summer, twice a week), we

covered 6 full chapters from Landau and Lifshitz’s Electrodynamics of Continuous

Media. These were Chpts. I. Electrostatics of Conductors, II. Electrostatics of Dielectrics,

IV. Static Magnetic Field, VII. Quasistatic Electromagnetic Field, IX. The

Electromagnetic Wave Equations, and XVI. Diffraction of X-rays in Crystals.

In addition, we covered two sections from ECM Chapter VI. Superconductivity, Sections

23 and 24 of L & L’s Classical Theory of Fields (on The electromagnetic field tensor and

Lorentz transformation of the field), Sections 123 and 124 from L & L’s Statistical

Physics, Part 1 (on the generalized susceptibility and the fluctuation-dissipation theorem,

respectively), a Lecture or two from Feynman’s lecture series (including the one on

Faraday’s law of induction) and several chapters from Purcell’s undergraduate E & M

book (mostly on relativity, as I recall).

Over ten year’s time, we covered 213 pages (just counting ECM, CTF, and SP)

comprising 55 sections (some were harder than others, none was easy!), including almost

all of the problems therein. Since there are 520 weeks in 10 years, we spend 2.4 weeks on

each page on average, or 9.45 weeks on each section (with a wide spread in each case).

Speaking for myself, it has felt great to struggle with such difficult but enriching material.

At this point, I feel satisfied with my grasp of every topic we covered, and have gained

just the sense of familiarity and confidence with electromagnetism that I’d hoped for

when we started.

In addition, it has been edifying beyond description to observe the growth in confidence

and skill of all the other participants, whose questions, comments, presentations, and

insights benefited everyone.

Although those last are too numerous to recount, my personal choice for the best question

ever was Aniruddha’s query about the physical significance of the tracelessness of the

energy-momentum tensor for the electromagnetic field, which led to a several-months-

long “wormhole” before resolving itself in a clear explanation. I’d also award a prize for

second-best question of all time to Chris Williams for asking whether the vanishing of the

imaginary part of the permittivity on the imaginary-frequency axis implies that no

dissipation occurs at zero (real) frequency.

I really like a recent comment Mary made about her experience in the group (she being,

along with Jeff and (almost) Vivian, a founding member who stayed the whole 10-year

course):

“It has been a real pleasure working through this text... I think some of the most

important lessons I've learned about science while in graduate school I've learned through

this book. These are mostly lessons about patience, and realizing if you don't take the

time to fully understand the current topic, your chances of fully understanding the next

topic are smallish. There is also the lesson of just having fun with work--yes, science can

be stressful, but the actual act of thinking about things is quite fun. That last part is

sometimes easy to forget when under pressure.”