User CBBAM

27 votes

6 answers

5k views

What is the connection between a mathematician and physicist's definition of a tensor?

asked Feb 13, 2023 at 9:29

15 votes

1 answer

1k views

What does it mean for a field to be defined by a measure?

asked Jan 25, 2023 at 3:40

13 votes

3 answers

2k views

What does the angular momentum vector really represent? [duplicate]

asked Nov 25, 2022 at 1:35

13 votes

2 answers

2k views

Trouble reconciling these two views on gauge theory

asked Oct 5, 2023 at 2:23

12 votes

2 answers

2k views

How to interpret quantum fields?

asked Dec 19, 2022 at 1:15

10 votes

3 answers

3k views

How do we know that all quantum fields are Fourier transforms of creation and annihilation operators?

asked Dec 23, 2022 at 8:43

10 votes

4 answers

6k views

Understanding Wikipedia's definition of a spinor

asked Nov 26, 2023 at 22:50

9 votes

2 answers

950 views

Why are test functions always taken to be Schwartz in quantum field theory?

asked Nov 5 at 19:49

9 votes

3 answers

2k views

Is turbulence more likely to form with the Euler equation as opposed to Navier-Stokes?

asked Aug 30, 2022 at 18:34

8 votes

3 answers

4k views

Why is the kinetic energy of a fluid given as an integral?

asked Nov 11, 2022 at 21:48

7 votes

3 answers

952 views

How does the absence of quadratic terms in the Lagrangian imply massless quanta?

asked Mar 24, 2023 at 4:44

7 votes

2 answers

400 views

Hilbert space of free theory vs interacting theory

asked Mar 27, 2023 at 17:33

7 votes

3 answers

700 views

How does one go from wavefunctions to fields?

asked Jul 27 at 2:34

5 votes

1 answer

150 views

Why do we rescale momenta after integrating out high momenta in Wilsonian renormalization?

asked Apr 16 at 6:59

5 votes

1 answer

311 views

Why must Grassmann algebras for Fermionic theories be infinite dimensional?

asked Dec 13 at 5:21

5 votes

1 answer

467 views

Why do different contours give different answers in the limit $\epsilon \rightarrow 0$ when calculating propagators?

asked Feb 8 at 21:11

5 votes

1 answer

320 views

Trouble understanding Wilsonian renormalization

asked Apr 11, 2023 at 8:23

5 votes

1 answer

389 views

What does it mean to apply a creation or annihilation operator to a free field, e.g. $\langle 0|a(p)\varphi(x)| 0 \rangle$?

asked Dec 19, 2022 at 0:35

5 votes

2 answers

818 views

Why does causality lead to different contours when calculating propagators?

asked Dec 26, 2022 at 22:39

5 votes

0 answers

81 views

Vorticity: what is the difference between $\nabla \times f$ and $\nabla \wedge f$? [duplicate]

asked Aug 14, 2022 at 4:24

4 votes

1 answer

311 views

Physically, how are constants like $c$ or $\hbar$ allowed to be unitless in natural units?

asked Oct 29, 2022 at 16:22

4 votes

2 answers

497 views

Mathematical definition of annihilation and creation operators

asked Sep 25, 2022 at 16:43

4 votes

2 answers

1k views

Why do we care about the canonical commutation relations?

asked Dec 9, 2022 at 2:18

4 votes

2 answers

893 views

Assigning initial conditions for Schrodinger's equation

asked Sep 18, 2022 at 21:42

4 votes

1 answer

219 views

Why is the $S$-matrix calculated using the free vacuum state and not the full interacting vacuum state?

asked Mar 7, 2023 at 8:05

4 votes

1 answer

321 views

How is the source term chosen when using path integrals?

asked Mar 14, 2023 at 4:56

4 votes

2 answers

489 views

Interpreting generating functional as sum of all diagrams

asked Feb 29 at 2:54

4 votes

2 answers

546 views

Making sense of stationary phase method for the path integral

asked Mar 5 at 6:39

4 votes

1 answer

613 views

Why are 2-point functions Green's functions?

asked Apr 2 at 21:59

3 votes

2 answers

267 views

Difference between renormalizable and super-renormalizable theories

asked Mar 26 at 17:43

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134 Questions

What is the connection between a mathematician and physicist's definition of a tensor?

What does it mean for a field to be defined by a measure?

What does the angular momentum vector really represent? [duplicate]

Trouble reconciling these two views on gauge theory

How to interpret quantum fields?

How do we know that all quantum fields are Fourier transforms of creation and annihilation operators?

Understanding Wikipedia's definition of a spinor

Why are test functions always taken to be Schwartz in quantum field theory?

Is turbulence more likely to form with the Euler equation as opposed to Navier-Stokes?

Why is the kinetic energy of a fluid given as an integral?

How does the absence of quadratic terms in the Lagrangian imply massless quanta?

Hilbert space of free theory vs interacting theory

How does one go from wavefunctions to fields?

Why do we rescale momenta after integrating out high momenta in Wilsonian renormalization?

Why must Grassmann algebras for Fermionic theories be infinite dimensional?

Why do different contours give different answers in the limit $\epsilon \rightarrow 0$ when calculating propagators?

Trouble understanding Wilsonian renormalization

What does it mean to apply a creation or annihilation operator to a free field, e.g. $\langle 0|a(p)\varphi(x)| 0 \rangle$?

Why does causality lead to different contours when calculating propagators?

Vorticity: what is the difference between $\nabla \times f$ and $\nabla \wedge f$? [duplicate]

Physically, how are constants like $c$ or $\hbar$ allowed to be unitless in natural units?

Mathematical definition of annihilation and creation operators

Why do we care about the canonical commutation relations?

Assigning initial conditions for Schrodinger's equation

Why is the $S$-matrix calculated using the free vacuum state and not the full interacting vacuum state?

How is the source term chosen when using path integrals?

Interpreting generating functional as sum of all diagrams

Making sense of stationary phase method for the path integral

Why are 2-point functions Green's functions?

Difference between renormalizable and super-renormalizable theories