Added: 5 times down vote for now! Down voter is this religion or physics, please try to explain your decision.
I'm confused about this.
In physics we know for a vacuum, but I think that there is a contradiction in this term. The quantum fluctuations are the phenomena that contradicts the vacuum existence because, according to them, the vacuum isn't the empty space. In vacuum the creation of particle-antiparticle pairs is allowed for small times and this is also proven in practice.
From the other side, the relativistic theory says about space-time that interactions like gravitation bend the vacuum (empty space). There seems to be a contradiction to me. If vacuum is an empty space then we can't bend it, because we can't bend something nonexistent. In other words: we can't bend 'nothing'.
Can empty space really exist in physics?
EDIT1: quote: Luboš Motl
"By definition, the space without energy is the space whose total value of energy is equal to 0."
But this space is nonexistent, so it is abstract and should exist only in our mind... Why is so? My second statement of this post says that in physics we cant bend nothing because such a bending is only thinking and not physics!
Another possibility is that space is unknown kind of energy, but this is contradiction in modern physics!
Can any physics believe that nothing exists? By mathematical logic no! And mathematic is elementary tool in physics. Anything other than that is religion!
Nothing (empty space without energy) is only a logical state!
EDIT3: quote: Roy Simpson:
The General Relativity Vacuum is a space-time model region without matter.
and Luboš Motl says: "By definition, the space without energy is the space whose total value of energy is equal to 0."
But this is only mathematical Euclidean space + time so this is only a mathematic and not physics! With other words: this is only a method of mathematical mapping. But, in real (not theoretic) physics we can't mapping empty things. Empty is only a logical state!
Roy Simpsons argumentation seems to me acceptable.
quote: Roy Simpson:
Einstein struggled with this too, and the problem has come to be known as the "Hole argument" within GR. You have to decide whether you are just interested in GR's vacuum (empty space) or the full physical vacuum which includes quantum aspects as well.