Physics, asked by singhjyotisingh1044, 1 year ago

Why density matrices in QFT are calculated only by going to Euclidean metric?

Answers

Answered by vrrunda
3
I have been reading a few papers on entanglement entropy. I noticed that whenever people calculate either the density matrix or the reduced density matrix of a specific region, it is usually done by first going to euclidean metric and then proceeding from there. Is this done purely for calculational simplicity or is there a more deeper reason? I also tried searching for papers where the calculation is done directly in Lorentzian metric, but wasn't able to find any. I would really appreciate if someone could shed light on this.
Answered by Anonymous
0

Explanation:

In theoretical physics, quantum field theory (QFT) is a theoretical framework that combines classical field theory, special relativity, and quantum mechanics[1]:xi (but notably not general relativity's description of gravity) and is used to construct physical models of subatomic particles (in particle physics) and quasiparticles (in condensed matter physics).

In theoretical physics, quantum field theory (QFT) is a theoretical framework that combines classical field theory, special relativity, and quantum mechanics[1]:xi (but notably not general relativity's description of gravity) and is used to construct physical models of subatomic particles (in particle physics) and quasiparticles (in condensed matter physics).QFT treats particles as excited states (also called quanta) of their underlying fields, which are more fundamental than the particles. Interactions between particles are described by interaction terms in the Lagrangian involving their corresponding fields. Each interaction can be visually represented by Feynman diagrams, which are formal computational tools, in the process of relativistic perturbation theory.

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