All Questions
5
questions
3
votes
1
answer
106
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How can we use saddle point approximation for a bounce solution which is not even a strict local minimum of the Euclidean action?
In calculating the false vacuum decay, the main contribution to the imaginary energy part of the Euclidean path integral comes from the bounce solution. And we somehow apply saddle point approximation ...
- 619
1
vote
1
answer
266
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How to Wick rotate the Yang-Mills instanton winding number?
How to Wick rotate the instanton number of Yang-Mills theory?
(Related to the earlier question Wick rotate the Yang-Mills $SU(N)$ gauge theory's field strength?)
My question is particularly about ...
- 4,336
19
votes
2
answers
2k
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How to understand "analytical continuation" in the context of instantons?
Since this is a subtle and interesting question to me. I will give a rather detailed description. I hope you can keep reading it and find it interesting too.
For simplicity, in the following I will ...
- 3,691
1
vote
1
answer
2k
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How does Euclidean Quantum Field Theory describe tunneling?
We know that Euclidean QFT originates from path integral formalism of
$$\langle\phi_f|e^{-\beta\hat{H}}|\phi_x\rangle.\tag{1}$$
We can understand that for $\beta\rightarrow\infty$, we can obtain the ...
- 3,691
7
votes
1
answer
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How can I understand the tunneling problem by Euclidean path integral where the quadratic fluctuation has a negative eigenvalue?
I came across the S. Coleman's seminal papers 'Fate of the false vacuum' (http://dx.doi.org/10.1103/PhysRevD.15.2929, http://dx.doi.org/10.1103/PhysRevD.16.1762) where he describes the tunneling ...
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