Showing posts with label Proca. Show all posts
Showing posts with label Proca. Show all posts

Friday, August 17, 2018

Relativistic Schrödinger equations

Amazon link

Note: some chapters of Robert Klauber's excellent book are downloadable for free.

---

In my intermittent progress through Robert Klauber's excellent "Student Friendly Quantum Field Theory" I'm currently working through the relativistic versions of the Schrödinger equation (prior to hitting QFT-proper).

These are indexed by spin. Schrödinger's non-relativistic equation which is the staple of introductory quantum mechanics courses, works for spin-1/2 fermions like the electron to which it is usually applied.

The most direct relativistic counterpart is Klein-Gordon, which Schrödinger considered first but couldn't make work for the hydrogen atom. This is because it actually applies to spin-0 particles (scalar bosons such as the Higgs particle).

The correct relativistic equation for the electron and other spin-1/2 fermions is named after Dirac, while vector bosons such as the photons (spin 1) have their own Proca equation.

So I was wondering if the spin-2 graviton has its own equation .. but then I recalled that quantum theory can't do gravity yet - see this.

Here's a convenient, semi-impenetrable table.