All Questions
5
questions
4
votes
1
answer
264
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What is the equivalent of causality in Euclidean field theory?
In Wick rotated quantum field theory where $t$ becomes $it$ and it has Euclidean metric signature. What would be the equivalent statement that events outside each others light-cones are disconnected ...
user84158
3
votes
0
answers
174
views
Analytic cotinuation between Minkowskian and Euclidean space, and causality
We can flip between Minkowkian and Euclidean signature by Wick rotation, and it is a well defined operation, provided there are no non - trivial singularities.
Now, Unitarity in Minkowskian space ...
- 1,182
4
votes
0
answers
398
views
Causality and wick rotation
What is the connection between causality and wick rotation?
I came across implication of this connection multiple times but can't find a rigorous explanation.
For example in the answer to Wick ...
- 861
10
votes
2
answers
1k
views
Euclidean QFT commutator vanishes for all spacetime separations?
In Minkowski spacetime, the commutator of the Klein-Gordon field operator with itself at different spacetime points evaluates to the advanced minus retarded Green's function of the classical theory,
...
- 695
10
votes
1
answer
7k
views
How does the Feynman's $i\epsilon$-prescription make the Feynman propagator causal?
The Feynman propagator is non-vanishing outside the light cone, but still manages to be in accord with causality. How is this achieved? What does the $i\epsilon$-prescription have to do with this?
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