Quantum vacuum fluctuation in BEC

[Adele]

TL;DR Summary

Propagation of phonon in BEC, several contributions

Hi, I have some problems with visualization (I'm trying to understand Jeff Steinhauer's experiment, but my questions are general).

Why the quantum vacuum fluctuations are guaranteed by the underlying pointlike atoms composing a BEC?

And if vacuum fluctuations generate excitations (i.e phonon) what is the link with the propagation of wave? Does this excitation produce waves? There are propagating waves plus excitation due to vacuum fluctuations?

And more specifically, he used the correlation between annihilation operators for demonstrated the Hawking radiation but why not the creation operators?
Thanks

 

[BigJDubs]

Quantum vacuum fluctuations arise due to the fact that atoms interact with each other in a BEC. The Heisenberg uncertainty principle states that there is an inherent uncertainty in the momentum and position of particles. This means that even in a vacuum, the particles can spontaneously and randomly fluctuate from their ground state to an excited state. These fluctuations can create excitations, or quanta of energy, which can propagate as waves, creating sound waves or other types of waves. As for Jeff Steinhauer's experiment, he used correlation between annihilation operators to demonstrate Hawking radiation because these operators describe the destruction of particles, which is how Hawking radiation is thought to occur. Creation operators on the other hand describe the creation of particles, which does not necessarily correspond to Hawking radiation.