Rozowsky1 Department of Physics, University of California at Los Angeles, CA 90095-1547 Abstract We show how Feynman diagrams may be evaluated to take … The phrase “Feynman diagram” is somewhat generic. 3. Feynman diagrams and low-dimensional topology Maxim Kontsevich October 6, 2006 We shall describe a program here relating Feynman diagrams, topology of manifolds, homotopical algebra, non … A Feynman diagram for the self-energy of a physical electron. There are, however, distinct rules for each. 10 Drawing Feynman diagrams If the scattering reaction involves composite particles (hadrons) first of all determine their quark decomposition making sure all quantum numbers add up consistently Then put at the left of the diagram the initial-state particles and at the right of the diagram … 8 Feynman Diagrams We now return to the scattering problem p1 +p2!q1 +q2 Setting Z to 1, the LSZ reduction and perturbation formula gives hq1;q2;outjp1;p2;ini = Z d4x1d4x2d4y1d4y2eiq1y1+q2y2 … Manually Calculating Transition Amplitudes It can be shown that interpreting Feynman diagrams as … Soon the diagrams … A vacuum Feynman diagram. It often covers both the diagrams and the process of constructing the mathematical ex-pression associated with the diagrams. The American theoretical physicist Rich-ard Feynman first introduced his diagrams in the late 1940s as a bookkeeping device for simplifying lengthy calculations in one area of physics—quantum electrodynamics, or QED, the quantum-mechanical description of elec-tromagnetic forces. Feynman diagrams the tool of choice. Figure 6. Feynman Diagrams and Cutting Rules J.S.