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Sven2009
  • Member for 3 years, 4 months
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34 votes
1 answer
3k views

Zero modes ~ zero eigenvalue modes ~ zero energy modes?

  • 7,340
31 votes
2 answers
17k views

What is the significance of the QCD scale parameter $\Lambda$?

  • 8,500
29 votes
2 answers
11k views

What are zero modes?

24 votes
1 answer
3k views

How do instantons cause vacuum decay?

20 votes
1 answer
5k views

How to Perform Wick Rotation in the Lagrangian of a Gauge Theory (like QCD)?

  • 512
19 votes
1 answer
1k views

What's the real resolution of the $U(1)_A$ problem?

  • 95.4k
16 votes
2 answers
6k views

The Spin Connection

  • 1,246
15 votes
2 answers
4k views

What is the difference between Chiral anomaly, ABJ anomaly, and Axial anomaly?

  • 159
14 votes
2 answers
2k views

Counting the number of propagating degrees of freedom in Lorenz Gauge Electrodynamics

  • 5,913
14 votes
1 answer
933 views

Interacting Fields in QFT

13 votes
2 answers
5k views

Variation of the metric with respect to the metric

  • 318
12 votes
1 answer
1k views

Can massive fermions have zero modes?

10 votes
1 answer
871 views

Understanding multiple instanton contributions to vacuum tunneling in a double potential well

  • 1,699
10 votes
2 answers
1k views

Question about physical degree of freedom in Maxwell Theory: Why Coulomb gauge can fix all redundant degree of freedom

8 votes
2 answers
3k views

How do Faddeev-Popov (FP) ghosts help path integrals?

  • 2,301
8 votes
1 answer
2k views

Dirac Equation in General Relativity

  • 343
7 votes
1 answer
894 views

The relationship between spin and spinor curvature

  • 121
7 votes
1 answer
7k views

Scalar field lagrangian in curved spacetime

  • 111
6 votes
1 answer
887 views

$U(1)$ abelian/axial/chiral anomaly in 4D

  • 301
6 votes
1 answer
1k views

Field action of linearized gravity associated with spin-2 particle in Thorne book

6 votes
2 answers
434 views

How can we have a quark condensate without a quark potential?

6 votes
2 answers
2k views

Proof of Goldstone's theorem

5 votes
2 answers
1k views

Why does the classical path give the dominant contribution in the path integral?

  • 24.2k
5 votes
1 answer
2k views

Power counting and (superficial) non-renormalizability

5 votes
2 answers
1k views

Possible divergence structures of a renormalizable and non-renormalizable theory

  • 24.2k
5 votes
1 answer
641 views

Obtaining the effective Lagrangian for axions from the spontaneous breakdown of Peccei-Quinn symmetry

  • 24.2k
4 votes
1 answer
655 views

Why doesn't a renormalizable $\phi^4$ theory have odd diagrams?

  • 43
4 votes
2 answers
656 views

The use of $a^\dagger(\mathbf{k}) = -i \int d^3x e^{ikx}\stackrel{\leftrightarrow}{\partial}_0 \phi(x)$ in the derivation of the LSZ-formula

4 votes
1 answer
760 views

R-matrix and S-matrix in QFT

  • 3,086
4 votes
1 answer
416 views

Convert propagators from Euclidean to Minkowski spacetime

  • 610