Minimal undergraduate curriculum
Modern physics consists of five domains, which are distinguished by their focus, methods and intent:
I. Theoretical physics
II. Phenomenology
III. Numerical physics (eg. lattice QCD, numerical gravity)
IV. Experimental and observational physics (eg. high energy experiment, observational astrophysics)
V. Applied and industrial physics
Of these, phenomenology and numerical physics are closer to theoretical than to experimental and observational physics, though they are less concerned with conceptual questions or mathematical rigor. Each of the five domains is further subdivided according to subject.
Competence in any of these five domains requires a good grasp of fundamental physics, which is the main focus of standard undergraduate programs. It is impossible to be a good phenomenologist, numerical physicist, experimental or observational physicist or even applied or industrial physicist without having a good grasp of the theoretical and mathematical underpinnings of fundamental physics.
A specialization in theoretical physics requires not only an excellent grasp of fundamental physics but also competence in advanced subjects (including areas of advanced mathematics) which are not covered at undergraduate level. Mathematical physics requires an excellent understanding of mathematics, which goes beyond what is expected of theoretical physicists.
A student interested in theoretical or mathematical physics will benefit much more from learning mathematics during undergraduate years than from focusing on lab work, since advanced theoretical physics subjects require graduate level mathematics. Theoretical and mathematical physicists do not deal with experiments or experimental data directly.
A standard undergraduate course in fundamental physics covers five core physics subjects:
1. Classical mechanics
2. Thermodynamics and statistical physics
3. Electromagnetism and special relativity
4. Quantum mechanics
5. General relativity and elements of cosmology
as well as the following seven core mathematics subjects:
1. Linear algebra and elements of abstract algebra
2. Real analysis and elements of complex analysis (the elementary part of analysis includes what in the US system is called "calculus")
3. ODEs
4. PDEs
5. Finite groups, Lie groups, Lie algebras and their representations
6. Functional analysis and operator theory
7. Differential geometry.
Each of these subjects can be covered at four levels:
Level 0: Elementary
Level 1: Introductory
Level 2: Intermediate
Level 3: Advanced.
Levels 2 and 3 correspond to the advanced undergraduate/beginning graduate and advanced graduate levels respectively. "Level -1" indicated below is preparatory, i.e. material that should normally be covered in high school. References at intermediate and advanced levels can be found here and here. Students who find the references below too easy are encouraged to try those instead. Students who find the elementary level too easy should jump directly to the introductory, intermediate or advanced levels.
Note. The minimal undergraduate curriculum detailed below is far from sufficient for doing quality research in any area of modern theoretical or mathematical physics. Students who wish to work in those subjects will have to learn much more at the graduate level. They are encouraged to try the intermediate and advanced levels during their undergraduate years on any topic which is of particular interest to them. Students who are serious about mathematical physics are encouraged to take at least some classes in the Mathematics department of their university, ideally as a replacement for elective labs or for elective courses concerned with subjects that fall outside the core areas of theoretical physics.
Some elementary (Level 0) and introductory (Level 1) references
A. Physics
Some standard elementary and introductory series to undergraduate physics are listed here and will not be repeated below. They cover all core physics subjects except for general relativity.
Elementary
Halliday, Resnick and Walker, Fundamentals of Physics
Alonso and Finn, Physics
Introductory
The Berkeley Physics Course, vols 1-4
Other recommended books by subject and level (out of four possible levels, 0-3), listed in approximate order of increasing difficulty.
Note. In some cases, introductory references are grouped by sublevels of difficulty which are indicated in increasing order.
1. Classical mechanics
Elementary
Kleppner and Kolenkov, An introduction to Mechanics
Introductory
1.1 Taylor, Classical mechanics
1.2 Goldstein et al, Classical Mechanics
Arnold, Mathematical Methods of Classical Mechanics
2. Thermodynamics and statistical physics
Elementary
Callen, Thermodynamics and an introduction to thermostatistics
Schroeder, An introduction to thermal physics
Kittel and Kroemer, Thermal physics
Introductory
2.1 Rief, Fundamentals of statistical and thermal physics
2.2 Kardar, Statistical physics of particles
Huang, Statistical mechanics
3. Electromagnetism and special relativity
Elementary
Griffiths, Introduction to electrodynamics
Introductory
Greiner, Classical electrodynamics
Zangwill, Modern electrodynamics
Brau, Modern problems in classical electrodynamics
Scheck, Classical field theory
French, Special relativity
Taylor and Wheeler, Spacetime physics
Resnick, Introduction to special relativity
Tsamparlis, Special relativity
4. Quantum mechanics
Elementary
Eisberg and Resnick, Quantum physics
Zettili, Quantum mechanics
Introductory
4.1 Townsend, A modern approach to quantum mechanics
Griffiths, Introduction to quantum mechanics
4.2 Shankar, Principles of quantum mechanics
Messiah, Quantum mechanics, vols 1 & 2
5. General relativity and elements of cosmology
Elementary
Hartle, Gravity: an introduction to Einstein's general relativity
Zee, Einstein gravity in a nutshell
Introductory
5.1 Carroll, Spacetime and geometry: an introduction to general relativity
Schutz, A first course in general relativity
5.2 Wald, General relativity
5.3. Hughston and Tod, An introduction to general relativity
Natario, An introduction to mathematical relativity
B. Mathematics
Preparatory and foundational subjects
Note. One cannot understand mathematics without a good grasp on its logical methods and basic proof theory. All aspiring theoretical physicists should be fluent in reading, understanding and composing mathematical proofs. They should also be able to read pure mathematics literature with ease. This is doubly so for mathematical physicists.
-1. Structure and basic methods of mathematical proofs
Hammack, Book of Proof
Lakatos, Proofs and refutations
Stewart and Tall, The foundations of mathematics
0. Set-theoretic foundations
Elementary
Halmos, Naive set theory
Introductory
Fraenkel and Bar-Hillel, Foundations of set theory
Kleene, Mathematical logic
Fraenkel, Abstract set theory
Core undergraduate subjects
1. Linear and abstract algebra
Elementary
Hoffman and Kunze, Linear Algebra
Introductory
Mac Lane and Birkhoff, Algebra
Halmos, Finite-dimensional linear algebra
Dummit and Foote, Abstract algebra
2. Real analysis and elements of complex analysis
Elementary
Spivak, Calculus
Piskunov, Differential and integral calculus, vols 1 & 2
Pugh, Real mathematical analysis
Palka, An introduction to complex function theory
Introductory
2.1 Apostol, Calculus, vols 1 and 2
Hardy, A course of pure mathematics
2.2 Courant, Differential and integral calculus, vols 1 & 2
Kolmogorov and Fomin, Introductory real analysis
Priestley, Introduction to complex analysis
2.3 Rudin, Principles of mathematical analysis
Conway, Functions of one complex variable
Stein and Shakarchi, Complex analysis
3. Ordinary differential equations (ODEs)
Elementary
Zill et al, Differential equations with boundary value problems
Brenner, Problems in differential equations
Introductory
Arnold, Ordinary differential equations
Perko, Differential equations and dynamical systems
Hirsch and Smale, Differential equations, dynamical systems and an introduction to chaos
4. Partial differential equations (PDEs)
Elementary
Olver, Introduction to partial differential equations
Berg and Mc. Gregor, Elementary partial differential equations
Introductory
Strauss, Partial differential equations: an introduction
Courant and Hilbert, Methods of mathematical physics, vols 1 & 2
5. Finite groups, Lie groups, Lie algebras and their representations
Elementary
Steinberg, Representation theory of finite groups: an introductory approach
Hall, Lie groups, Lie algebras and their representations
Introductory
Serre, Linear representations of finite groups
Brocker, Representations of compact Lie groups
6. Functional analysis and operator theory
Elementary
Bachman and Narici, Functional analysis
Retherford, Hilbert space:compact operators and the trace theorem
Introductory
Kresyzig, Introductory functional analysis with applications
Young, An introduction to Hilbert space
Helmberg, Introduction to spectral theory in Hilbert space
Halmos, A Hilbert space problem book
7. Differential geometry
Elementary
O'Neill, Elementary differential geometry
Topogonov, Differential geometry of curves and surfaces
Lee, Introduction to smooth manifolds
Introductory
Munkres, Topology
Spivak, A comprehensive introduction to differential geometry, vol 1
Lee, Riemannian manifolds: an introduction to curvature