Standard Model and Beyond · Problem 2.1

Lie Groups, Lie Algebras, and Symmetries

Physics — Particle Physics · free-complex-scalar-field-hamiltonian

Problem

From (A.7), the Hamiltonian for a free complex scalar field is H=∫d3x⃗[(∂ϕ†∂t)(∂ϕ∂t)+(∇⃗ϕ†)⋅(∇⃗ϕ)+m2ϕ†ϕ].H = \int d^3\vec{x} \left[\left(\frac{\partial\phi^\dagger}{\partial t}\right)\left(\frac{\partial\phi}{\partial t}\right) + (\vec{\nabla}\phi^\dagger)\cdot(\vec{\nabla}\phi) + m^2\phi^\dagger\phi\right]. Show that H=∫d3p⃗(2π)32EpEp[a†(p⃗)a(p⃗)+b†(p⃗)b(p⃗)].H = \int \frac{d^3\vec{p}}{(2\pi)^3 2E_p} E_p\left[a^\dagger(\vec{p})a(\vec{p}) + b^\dagger(\vec{p})b(\vec{p})\right]. Assume that HH is normal ordered.

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