1. wan ahmad tajuddin wan abdullah jabatan fizik universiti malaya
Quantum fields
wan ahmad tajuddin wan abdullah
jabatan fizik universiti malaya

2. Special relativity c as limitting velocity Time is relative
Spacetime – Lorentz invariance
Locality - no action at a distance

3. Quantum mechanics Wave-particle duality Uncertainty principle
Measurement – wave function collapse - entanglement

4. Relativistic quantum mechanics
Non-relativistic:
Schroedinger equation
Relativistic:
Klein-Gordon equation
non-linear!
Linearize:
SPIN
 ANTIPARTICLES
Dirac equation

5. Fields Force as fields – Gravitational [Newton’s gravitational law]
Electromagnetic [Maxwell’s equation]
Extended in space
Action at a distance

6. Quantum fields waves ~ particles potentials ~ virtual particles
Absolute values at every point in space  probabilistic distribution of values (from virtual particles) at every point in space
Absorption/scattering of virtual particles  “force”

7. Path integrals Classical mechanics – trajectories
Euler-Lagrange equation
Langrangian
extremise ‘action’ least action principle
Quantum paths
probability amplitude

8. Feynman diagrams Diagrammatic representation
Facilitate calculations – Feynman rules

9. Perturbation theory
Lowest order approximation – lowest order diagrams (least number of vertices)
Higher order – include higher order diagrams
                        Theory         gs =
                        Experiment       gs =
                                                    + 
drawing by Tom Brown

10. Quantum field theory of fundamental forces
Gauge fields (bosons) mediating interactions –
EM – photons
Weak nuclear force – W, Z bosons
Strong nuclear force – gluons
GAUGE SYMMETRY between fields
UNIFICATION of forces into bigger symmetry

11. Higgs Spontaneous symmetry breaking Give masses to particles
Higgs particle