Tag: Klein-Gordon equation

• Classical Field Theory and the Lagrangian: From a Variational Principle for Infinitely Many Degrees of Freedom to Noether's TheoremThe Lagrangian density from the continuum limit of coupled oscillators, the Euler–Lagrange equations from the variational principle, and Noether's theorem for the Klein–Gordon field.PhysicsQuantum Field TheoryGraduateClassical field theoryLagrangian densityKlein-Gordon equationNoether's theoremConserved current~34 min
• Why We Need Quantum Field Theory: One-Particle Quantum Mechanics Is Incompatible with RelativityRelativity grafted onto one-particle quantum mechanics yields negative energies, a negative probability density and acausal propagation. Quantizing the field is the only way out.PhysicsQuantum Field TheoryGraduateQuantum field theorySecond quantizationKlein-Gordon equationAntiparticlesCausality~37 min