# Imaginary Action

1. May 1, 2007

### plxmny

Friends,

I am reading that the standard way to discuss tunneling is via imaginary action.
The reference cited is J.S. Langer, Ann. Phys. 1967.

(1) What is the full name of Ann. Phys. so I can look up this paper?
(2) What textbook can I acquire to learn this technique?

2. May 1, 2007

### nrqed

Annals of Physics

3. May 1, 2007

### plxmny

Thank you - I checked the local university library but they don't have back to 1967 without jumping through hoops. I'll try another tomorrow.

In the meantime I hope someone can shed some light on this imaginary action technique for me.

I tried posting the same query to crackpot-land (google) so we'll see.

4. May 2, 2007

### TriTertButoxy

The imaginary action technique might be a fancy term to describe Feynman's path integral formalism, whose central equation is

$$\langle x_b|e^{-i \hat{H} t/\hbar}|x_a\rangle=\int\mathcal{D}x(t)\,e^{i S[x(t)]/\hbar}\,,$$​

where the LHS is the amplitude for a particle to travel (or tunnel) from position $x_a$ to $x_b$. The imaginary action might be the quantity in the exponent in the RHS.

5. May 2, 2007

### plxmny

I think that you are correct. I also heard that landau lifschitz nrqm has an exposition of the technique. i am trying to get a copy now to check.

Also I just learned that the cited reference was re-published in 2000 so I might have some luck there. I will let you all know.

kisses,
plxmny