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In QFT, fields are everywhere. The fields in quantum field theory are mathematical tools, they are not physical entities. But to support a field, you need a m
by danbruc 10y ago
In QFT, fields are everywhere.
The fields in quantum field theory are mathematical tools, they are not physical entities.
But to support a field, you need a mechanism that allows causal propagation - which is exactly what isn't allowed across an event horizon.
But that is only a one-way thing - the future light cones of events inside the event horizon are contained inside the event horizon but the future light cones of events outside the event horizon certainly overlap the inside of the black hole.
- vanderZwan 10y ago> The fields in quantum field theory are mathematical tools, they are not physical entities. Still, they only maintain physical relevance as long as they are continuous, no? Otherwise you literally have a break in reality.
- danbruc 10y agoDo you mean that they can not have holes?
- guitarbill 10y ago> a break in reality. Such as a singularity (e.g. gravitational)? I think in Physics (just as when analysing functions), the interesting things happen when you approach such limits.
- evanb 10y agoCan you explain what you mean by > The fields in quantum field theory are mathematical tools, they are not physical entities. If you mean that the world itself is not the mathematics then I can accept it (although I might resist, the philosophical rejection of things like Tegmark's Mathematical Universe Hypothesis), but if you mean that what we actually have is a bunch of particles doing one thing or another, I must object, because it is extremely difficult to explain nonperturbative phenomena like instantons or sphaelerons if you have that attitude.
- danbruc 10y agoQuantum fields have gauge symmetry so they do not have any definite values, you can assume them to have more or less any value as long as you are consistent. My views on this topic are heavily influenced by Nima Arkani-Hamed and here [1] are 30 seconds from a lecture where he is very explicit about this. But I am aware that this is not really a topic with universal agreement, at least this is what it looks to a non-physicist like me. And looking at your user profile I am pretty sure you are going to tell me that I am asking for to much realism. [1] https://www.youtube.com/watch?v=tnA7bh7dTqY&t=1669 https://www.youtube.com/watch?v=tnA7bh7dTqY&t=1669