Quantum Field Theory Deserves Extra Help

Extra material for “Quantum Theory for Mathematicians”

then so is the curve x(−t), as is easily verified by direct computation. (Note that d/dt(x(−t)) = ẍ(−t), since the two derivatives pull out two minus signs.) In terms of trajectories in phase space, we note that dx(−t)/dt = −ẋ(−t). This means that the momentum of the particle along the time-reversed trajectory is the negative of the momentum along the original trajectory. We may therefore formu...

Effective Field Theory, Renomalizability and Extra Dimensions

We discuss in this paper two ways of defining the concept of “effective field theory”: effective field theory defined by low energy effectiveness and effective field theory defined by 4D effectiveness out of higher dimensions. We argue that these two views are actually equivalent, that effective field theories at low energy can in fact be regarded as field theories of higher dimensions confined...

Effective Field Theory, Renormalizability and Extra Dimensions

We discuss in this paper two ways of defining the concept of “effective field theory”: effective field theory defined by low energy effectiveness and effective field theory defined by 4D effectiveness out of higher dimensions. We argue that these two views are actually equivalent, that effective field theories at low energy can in fact be regarded as field theories of higher dimensions confined...

Quantum Field Theory Course

Part I. Classical Mechanics 9 0. Intro 9 0.1. Mechanical systems 9 0.2. Lagrangian and Hamiltonian formulation 9 1. Lagrangian approach 10 1.1. Manifolds 10 1.2. Differentiation 11 1.3. Calculus of Variations on an interval 11 1.4. Lagrangian reformulation of Newton‘s equation 13 2. Hamiltonian approach 14 2.1. Metrics: linear algebra 14 2.2. The passage to the cotangent vector bundle via the k...

Relativistic Quantum Field Theory