There used to be a Road to Reality discussion forum, now archived. There's a sorted list of solutions from the forum.
Some solutions and comments of my own:Sec. 9.7 Some more on hyperfunctions
Exercise 15.5 Mapping the 3-sphere to the tangent bundle on the 2-sphere
Exer.15.14 Model of a gauge connection on the complex plane
Section 16.2 The secret behind magic circles
Exer.16.8 A function from the quarter-plane to the naturals
Exer.18.5 Self-dual and anti-self-dual planes
Exer.18.7 Geometry on the velocity vector hyperboloid
Exer.19.14 Discrete analogue of the stress-energy tensor?
Exer.19.18 trace-reversed Ricci tensor has 0 divergence
Exer.19.16 Ricci tensor
has info about volume
a nice illustration of Lie derivatives
Exer.20.8 Taylor expansion of the equilibrium Hamiltonian
Exer.20.15 Symplectic form is unchanged by Hamiltonian evolution
Exer.22.9 Heisenberg equation of motion
Exer.22.11 Eigenvectors of a normal operator are orthogonal.
Exer.22.12 Amplitude <φ|ψ> = 1 only if φ proportional to ψ
Exer.23.3 Why does the singlet state have 0 spin?
Exer.23.4 Entangled state IS a product of states
Exer.23.9 Counting boson states
Exer.23.10 Quantum teleportation
Exer.24.3 Just a comment: An example of a normalizable state where momentum has a definite magnitude
Exer.24.7 relativistic invariance of the Dirac equation
Exer.24.9 Representing Clifford elements as matrices
Exer.25.6 Particle octet
Exer.25.9 Dual gauge curvature
Exer.26.5 Positive and negative frequency solutions to Maxwell equations
Exer.27.9 Putting MANY MANY little gas molecules back into Pandora's box
Exer.27.16 Isotropy and homogeneity: This problem has a counterexample!
Exer.28.2 Electroweak symmetry breaking
Exer.28.4 Exponential de Sitter metric
Exer.28.6 Ricci tensor is proportional to the metric tensor in (anti)de Sitter space
Exer.29.7 Pure-state density matrices
Exer.29.13 Density matrices for spin 1 EPR pairs
Exer.30.3 Black hole temperature
Exer.30.10 Gravitational time dilation
Exer.30.12 Uncertainty in ∂/∂t from energy to move mass distribution away from its potential
Exer.30.12 An easier proof
Exer.30.13 A free particle can't be in an energy eigenstate
Exer.31.6 Symplectic manifold from a Riemannian manifold with complex structure
Exer.32.2 Contracting a self-dual tensor with an anti self-dual tensor
Exer.33.2 Compactified Minkowski space!
Exer.33.5 Compactified Minkowski space as a conic section
Exer.33.8 The celestial sphere is a conformal manifold
Exer.33.11 A 0-length twistor is associated with (at least one) spacetime event
Exer. 33.16 The plane of points incident to a twistor is self-dual. Anti self-dual for dual twistor.
Exer. 33.18 The center of a twistor configuration can't be regarded as the path of a spinning particle
Exer. 33.19 Why is the twistor commutator a real number?
Exer. 33.23 See the answer to Exercise 33.24
Exer. 33.24 Massless free field equation for a photon = Maxwell's equations in empty space
Sec. 33.9 First analytic sheaf cohomology of the complex plane
Sec. 33.11 Making
curved twistor space by
drying paint. Also the answer to