Here are my solutions to various problems in the textbook *Quantum Field Theory for the Gifted Amateur*, by Tom Lancaster and Stephen J. Blundell (Oxford University Press, 2014). Obviously I can't offer any guarantee that all the solutions are actually *correct*, but I've given them my best shot.

**These solutions are the only ones that I've worked out so far, so please don't ask me to post "the rest of the chapters" as I haven't worked on those yet. I will get to them eventually.**

**Chapter 1 - Lagrangians**

Exercises

1.1, 1.2, 1.3, 1.4, 1.5, 1.6

**Chapter 2 - Simple harmonic oscillators**

**Chapter 3 - Occupation number representation**

**Chapter 4 - Making second quantization work**

- 4.1 Field operators for the infinite square well
- 4.2 Second quantizing a single-particle operator

- 4.2 Second quantizing operators – examples
- 4.3 Second quantizing the tight-binding hamiltonian

**Chapter 5 Continuous systems**

Exercises

5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 5.10

**Chapter 6 A first stab at relativistic quantum mechanics**

Exercises

6.1

**Chapter 7 Examples of Lagrangians, or how to write down a theory**

Exercises

7.1, 7.2, 7.3, 7.4

**Chapter 8 The passage of time**

**Chapter 9 Quantum mechanical transformations**

**Chapter 10 Symmetry**

Exercises

10.1, 10.2, 10.3, 10.4

**Chapter 11 Canonical quantization of fields**

**Chapter 12 Examples of canonical quantization**

Exercises

12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7

**Chapter 13 Fields with many components and massive electromagnetism**

Exercises

13.1, 13.2, 13.3, 13.4

**Chapter 14 Gauge fields and gauge theory**

**Chapter 15 Discrete transformations**

**Chapter 16 Propagators and Green's functions**

Exercises

16.1, 16.2, 16.3, 16.4

**Chapter 17 Propagators and fields**

Exercises

17.1, 17.2, 17.3, 17.4, 17.5

**Chapter 18 The S-matrix**

Exercises

18.1, 18.3, 18.4, 18.5

**Chapter 19 Expanding the S-matrix: Feynman diagrams**

Exercises

19.1, 19.2, 19.3, 19.4

**Chapter 20 Scattering theory**

**Chapter 21 Statistical physics: a crash course**

**Chapter 22 The generating functional for fields**

**Chapter 23 Path integrals: I said to him, 'You're crazy'**

**Chapter 24 Field integrals**

Exercises

24.1, 24.2, 24.3, 24.4

**Chapter 25 Statistical field theory**

- Example 25.4: statistics of the free scalar field
- I have no solution for problem 25.5. If anyone has a hint as to how this can be done, please leave a comment or contact me via the comments page. The solution to 25.6 was kindly provided by Pedro Dardengo Mesquita.

Exercises

25.2, 25.3, 25.4, 25.6

**Chapter 26 Broken symmetry**

Exercises

26.1, 26.2, 26.3, 26.4

**Chapter 27 Coherent states**