Basic Training in Condensed Matter Theory

Erich Mueller, James Sethna, Craig Fennie, Eun-Ah Kim

Physics 7654, Spring 2009, WF 2:30-4:00, Rockefeller 230

Condensed matter theory is an enormous, rich, evolving field which is impossible for a single professor to explain or even describe in a single graduate course. In order to help our students navigate this varied terrain, Cornell's condensed-matter theory group has developed Basic Training in Condensed-Matter Theory, a challenging, modular course taught once per year by a rotation of four condensed-matter theorists. Students are exposed to a different set of active research areas each year, and learn sophisticated analytical and numerical methods in the extensive exercises. This year our course replaces the traditional many-body physics course 654, and will incorporate some of the tools and concepts from that field. Tentatively, we plan to cover
Jan 21 - Feb 13 James Sethna (, Clark 528) Continuum Theories of Crystal Defects Grader: Yong Chen (
Feb 18 - Mar 13 Erich Mueller (, Clark 514a) Probes of Cold Atoms Grader: Stefan Natu (
Mar 25 - April 10 Craig Fennie (, Clark 226) Competing Ferroic orders: the magnetoelectric effect Grader: Johannes Lischner (
April 15 - May 1 Eun-Ah Kim (, Clark 507) Quantum Criticality Grader: Kaden Hazzard (
The various modules may involve weekly homework, daily "teasers", and small projects. First-year students are welcome, but the course will be at a high level of sophistication; we expect background in condensed matter physics at least equivalent to Ashcroft and Mermin. Experimentalists and others interested in working through two or more modules are encouraged to register for the class. All are welcome to audit and participate as time and background permit. Pass-fail.

For more information, please contact any of the instructors.

Quantum Criticality

Quantum Criticality -- Teasers

Teaser 1: Due Wednesday April 15 Teaser 1

Quantum Criticality -- Lecture Notes

Syllabus Wednesday April 15 Syllabus
Syllabus Wednesday April 15 Lecture 1


Multiferroics -- Homework

Homework 1: Due May 1, 2009 Homework 1

Multiferroics -- Teasers

Teaser 1: Due Friday April 3 Teaser 1 Solutions

Multiferroics -- Lecture Notes

March 25 Lecture 1
April 1 Lecture 2
April 3 Lecture 3
April 8 Lecture 4
April 10 Lecture 5

Probes of Cold Atoms

Probes of Cold Atoms -- Teasers

Teaser 1: Due Wednesday Feb 18 teaser1.pdf
Teaser 2: Due Friday Feb 20 teaser2.pdf
Teaser 3: Due Wednesday Feb 25 teaser3.pdf
Teaser 4: Due Friday Feb 27 teaser4.pdf
Teaser 4: Due Friday Mar 3, 2009 teaser5.pdf

Probes of Cold Atoms -- Lecture Notes

Lecture 1: Wednesday Feb 18 OpticalAbs.pdf
Lecture 2: Wednesday Feb 20 CollectiveModes.pdf
Lecture 4: Wednesday Feb 25 Helium.pdf

Continuum Theories of Crystal Defects

Teasers and other info can be found at: Sethna's Basic Training site. Synopsis (as interpretted by Erich Mueller)
Jan 21, 2009

Q: Why do continuum theories work?

A: Because we are interested in slow long length-scale properties.

Q: What are the relevant continuum fields for any system?

A: Conserved quantities (density, energy density, momentum density) and broken symmetries (magnetism, superconducting order,...).

teaser: Why can't we run faster than the speed of sound

Jan 22, 2009 Q: Why are we so weak?

A: dislocations.

Q: Why are we so strong?

A: composite materials.

Discussion of how to generate most general continuum free energy consistent with symmetries. Example (multiferroics). Discussion of boundary terms.

Teaser: Boundary terms can stabilize defects.