User jkb1603

11 votes

Accepted

Does local mean infinitesimally small?

answered Nov 20, 2020 at 15:02

6 votes

Accepted

Trouble deriving expression for differential scattering cross section from $S$-matrix

answered Jan 9, 2021 at 17:18

5 votes

Accepted

How come $\frac{d}{dt}\left(\frac{\partial {r_i}}{\partial {q_j}}\right) = \frac{\partial {\dot r_i}}{\partial {q_j}}$ in Lagrangian mechanics?

answered Dec 11, 2018 at 12:29

4 votes

Accepted

Do "tadpole diagram with two external legs" always vanish in massless theories?

answered Oct 11, 2021 at 9:27

3 votes

About the physical, measurable coupling constants, after renormalization

answered Jan 12, 2021 at 17:21

3 votes

Replacing pole with delta function in Peskin and Schroeder

answered May 16, 2019 at 22:08

3 votes

How to use the Poisson Bracket to generate a finite Lorentz transformation?

answered Oct 14, 2020 at 10:00

2 votes

Accepted

Why is the creation operator of a particle in the conjugate field operator?

answered Oct 8, 2020 at 16:02

2 votes

Accepted

Intrinsic Curvature of a Cylinder

answered Dec 12, 2020 at 12:57

2 votes

Feynman rules out of the Lagrangian

answered Nov 7, 2018 at 23:04

2 votes

Accepted

Finding conjugate momentum of field in Dirac Lagrangian

answered Nov 12, 2020 at 15:11

2 votes

$q^2=4m^2$ as the threshold for creation of a real electron-positron pair

answered Jan 14, 2021 at 15:57

2 votes

Accepted

Gauge invariance of loop Diagrams

answered Jan 23, 2021 at 15:50

2 votes

LSZ reduction formula for free fields

answered Jan 24, 2021 at 10:20

2 votes

Accepted

Collinear factorisation in QCD: why can we multiply probabilities?

answered Feb 9, 2021 at 17:44

2 votes

Accepted

Why Goldstein's book is claiming that radius and angle doesn't contain time variable even there is $\dot{r}$ and $\dot{\theta}$?

answered Sep 9, 2021 at 12:59

2 votes

Accepted

$CP^N$ model in Peskin & Schroeder problem 13.3

answered Jun 2, 2022 at 14:02

2 votes

Accepted

One-loop diagram calculation: Wick rotation and gamma matrices

answered Sep 21, 2021 at 9:40

2 votes

Relationship between minima of scalar potential and mass of particles in the theory?

answered Sep 22, 2021 at 17:05

2 votes

Do the operators $\hat{P}^i=-i\partial^i, ~\hat{J}^{ij}=i(x^i\partial^j-x^j\partial^i),$ ever arise in QFT as momentum and angular momentum operators?

answered Oct 1, 2021 at 9:01

1 vote

Accepted

Commutators in Poincare algebra

answered Nov 5, 2021 at 13:11

1 vote

Confusion on the renormalizability and the dimension of coupling constant (From Srednicki's book)

answered Sep 13, 2021 at 15:59

1 vote

Deep inelastic and Bjorken limit

answered Oct 12, 2020 at 10:58

1 vote

Charge conjugation of fields

answered Oct 19, 2020 at 9:59

1 vote

Schrödinger wavefunctional quantum-field eigenstates

answered Mar 3, 2020 at 15:59

1 vote

Accepted

Why the Feynman diagram with loops attached to external legs is irrelevant to the $T$-matrix?

answered Sep 8, 2020 at 17:10

1 vote

Accepted

Relation between Short Wavelength Physics and Long Distance Physics

answered Aug 28, 2021 at 18:24

0 votes

Fermion masses and $SU(2)$ symmetry

answered Sep 10, 2020 at 12:13

0 votes

Accepted

Newton's equation under time translation

answered Sep 11, 2020 at 12:35

0 votes

Trace of multi-index operator in path integral?

answered Sep 11, 2020 at 13:22

Stack Exchange Network

37 Answers

Does local mean infinitesimally small?

Trouble deriving expression for differential scattering cross section from $S$-matrix

How come $\frac{d}{dt}\left(\frac{\partial {r_i}}{\partial {q_j}}\right) = \frac{\partial {\dot r_i}}{\partial {q_j}}$ in Lagrangian mechanics?

Do "tadpole diagram with two external legs" always vanish in massless theories?

About the physical, measurable coupling constants, after renormalization

Replacing pole with delta function in Peskin and Schroeder

How to use the Poisson Bracket to generate a finite Lorentz transformation?

Why is the creation operator of a particle in the conjugate field operator?

Intrinsic Curvature of a Cylinder

Feynman rules out of the Lagrangian

Finding conjugate momentum of field in Dirac Lagrangian

$q^2=4m^2$ as the threshold for creation of a real electron-positron pair

Gauge invariance of loop Diagrams

LSZ reduction formula for free fields

Collinear factorisation in QCD: why can we multiply probabilities?

Why Goldstein's book is claiming that radius and angle doesn't contain time variable even there is $\dot{r}$ and $\dot{\theta}$?

$CP^N$ model in Peskin & Schroeder problem 13.3

One-loop diagram calculation: Wick rotation and gamma matrices

Relationship between minima of scalar potential and mass of particles in the theory?

Do the operators $\hat{P}^i=-i\partial^i, ~\hat{J}^{ij}=i(x^i\partial^j-x^j\partial^i),$ ever arise in QFT as momentum and angular momentum operators?

Commutators in Poincare algebra

Confusion on the renormalizability and the dimension of coupling constant (From Srednicki's book)

Deep inelastic and Bjorken limit

Charge conjugation of fields

Schrödinger wavefunctional quantum-field eigenstates

Why the Feynman diagram with loops attached to external legs is irrelevant to the $T$-matrix?

Relation between Short Wavelength Physics and Long Distance Physics

Fermion masses and $SU(2)$ symmetry

Newton's equation under time translation

Trace of multi-index operator in path integral?