I had an interesting email from a Buddhist living in Ireland on the subject of matter creation and space time and the unruh effect.
there is not as of yet any consensus about what a complete model of the fundamental structure of spacetime will look like. Personally, if I was to hazard a guess, and based on all the various models that have been proposed, I’d say that particles are not fundamental entities with independent existence at all, but rather observer-dependent artefacts. At the most immediate level, they are probably best understood as representing the relationship between an observer, and a region of spacetime. If that relationship changes, so do notions of “number of particles” - hence we get phenomena such as the Unruh effect, Hawking radiation, etc. Also, properties of these particles themselves largely depend on considerations of symmetry, so depend on the structure of spacetime and other fields, both large scale and small scale. It may simply not be meaningful to speak of a “particle” as something that exists independently of an observer and his relative orientation in spacetime, with spacetime itself of course also being a dynamic entity. So it’s really more of a vast, intricate, interdependent network of relationships, than merely a collection of separate entities.
Markus, I presume.
I certainly came out of my quantum chemistry course feeling that the electron is more of a wavelike thing than a Newtonian "particle" and I've been a bit suspicious of the idea of a "particle" ever since, the usefulness of the concept notwithstanding. When you think about it, a "particle" is a fairly improbable thing, with its notional mass, charge and "spin" but lack of physical extension. It looks a lot like a physicist's approximation to make the maths tractable. So it is not too surprising that, as with all approximations, it breaks down under certain circumstances.