It seems like a lot of pop science gets thrown around when explaining vacuum energy.
For instance, our QFT lecturer descried the non-interacting field theory vacuum energy as 'purely Heisenberg Uncertainty Principle energy for particle-antiparticle pairs popping in and out of existence' while the interacting field theory vacuum as 'this combined with them being able to exchange virtual particles'.
How correct is this? Is there a more precise explanation of the differences between the non-interacting and interacting field theory vacuum states, and why, for instance, we can drop the vacuum energy contribution in non-interacting field theories but not in interacting field theories?
Is it true that the non-interacting vacuum is kind of irrelevant since it cannot affect anything?