Exploring Vacuum Fluctuations: Particle Creation and the Casimir Effect

[EL]

I found a .pdf-file and there is written:
Define the vacuum state as the state with no photons in any mode. Thus the vacuum energy is:
and then the pic.

Why can he drop the term 1/2?

Since lambda takes on two values (polarizations)...?

 

[Sterj]

Another question:

We describe the ground state energy of the em-field with harmonic oscillators beeing at lowest energy level.

Now, someone told that the ground state vibration of the em-field are the photons, sounds logically (marlon) if we are in QFT.

If we are in vacuum and "watch" at the vacuum fluctuation there must always be a particle and its antiparticle exist. In the case of the photon it has to be two photons (because the photon is its own antiparticle).

1. Can the annihilation and creation of this pairs be explained with QFT where photons are vibrations? I mean you can't really add a photon to the zero point oscillation of the em field because then the em field isn't really in ground state. What I think is that these zero point energy of the em field is just the average energy of the field (marlon's posted formula).

2. If we work in QM the particle are wave (packets). So if I wonna explain this creation and annihilation of the two photons I have to do it as follows:

"Creation: HUP allows to create a particle and an antiparticle.
Lifetime: Both wave packets are flying around, simply said.
Annihilation: These wave packets interfer and thus energy is given back to vacuum"

 

[Creator]

The Casimir plates idea is essentially static. Is there any proposal for a dynamic version, in which some changing phenomenon which produces a (possibly moving) region in which the vacuum energy density is less than in its surroundings?

Excellent question, selfAdjoint. The answer is yes. I have seen reports confirming that standing wave patterns can be created with oscillating walls which can locally lower (or raise) the energy density in certain regions in the cavity.

O. Meplan has shown that, due to oscillating walls, in principle the vacuum fluctuations inside the cavity can be made to increase exponentially, and gives the experimental possibility & feasability to be able to observe photon creation from the vacuum!
See:
"Exponential Growth of the the energy of a Wave in a 1D Vibrating Cavity...",O. Meplan & C. Gignoux, Physical Review Lett, Vol.76, #3, pg.408, 1996.

Creator

--He who laughs last thinks slowest.--