|MadSci Network: Physics|
thank you for that interesting question. I have seen an article on the net, What a Rindler Observer Sees in a Minkowski Vacuum, where the authors argue that an observer accelerating relative to another observer has a different vacuum state. They define the vacuum for an observer being the state in which he sees no particles. The other observer accelerating relative to the first one will actually see particles in that state. The vacuum state depends on the observer. Observers moving at constant speed relative to each other will see the same vacuum state.
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