User SRS

65 votes

3 answers

7k views

Idea of Covering Group

asked Jan 31, 2014 at 1:31

65 votes

6 answers

10k views

Why does a system try to minimize its total energy?

quantum-mechanics classical-mechanics statistical-mechanics equilibrium dissipation

asked May 11, 2016 at 20:27

30 votes

2 answers

3k views

Scattering, Perturbation and asymptotic states in LSZ reduction formula

quantum-field-theory hilbert-space scattering vacuum s-matrix-theory

asked Oct 1, 2015 at 13:30

25 votes

5 answers

5k views

Newton's law requires two initial conditions while the Taylor series requires infinite!

newtonian-mechanics classical-mechanics mathematical-physics differential-equations

asked Jun 25, 2018 at 12:48

24 votes

1 answer

6k views

Self-adjoint and unbounded operators in QM

quantum-mechanics mathematical-physics operators hilbert-space

asked Mar 7, 2014 at 18:19

24 votes

2 answers

3k views

Relation between Wilsonian renormalization and Counterterm Renormalization

quantum-field-theory field-theory renormalization effective-field-theory

asked Feb 17, 2017 at 15:41

23 votes

3 answers

7k views

Symmetry Breaking And Phase transition

condensed-matter solid-state-physics phase-transition symmetry-breaking

asked Mar 26, 2014 at 10:20

23 votes

2 answers

2k views

What is the conclusion from Aharonov-Bohm Effect?

quantum-mechanics electromagnetism gauge-theory topology aharonov-bohm

asked Feb 17, 2014 at 11:32

22 votes

2 answers

7k views

What does a $\rm SU(2)$ isospin doublet really mean?

nuclear-physics standard-model group-theory group-representations isospin-symmetry

asked Feb 2, 2014 at 3:05

20 votes

3 answers

2k views

In what sense is the proper/effective action $\Gamma[\phi_c]$ a quantum-corrected classical action $S[\phi]$?

quantum-field-theory lagrangian-formalism path-integral action 1pi-effective-action

asked Jun 7, 2017 at 7:34

18 votes

3 answers

17k views

Constructing Lagrangian from the Hamiltonian

classical-mechanics lagrangian-formalism mathematical-physics hamiltonian-formalism hamiltonian

asked Jun 20, 2015 at 17:26

18 votes

1 answer

4k views

Does the number density of photons $n_\gamma\approx 10^8 \:\mathrm m^{-3}$ refer to CMB photons only?

cosmology astrophysics cosmic-microwave-background baryogenesis leptogenesis

asked Jul 28, 2015 at 8:37

16 votes

2 answers

3k views

Rest mass of phonon: is this concept definable?

quantum-field-theory special-relativity condensed-matter mass phonons

asked May 19, 2016 at 17:25

16 votes

2 answers

906 views

Why is Higgs particle detected much later than top quark when it's lighter? [duplicate]

particle-physics standard-model higgs large-hadron-collider particle-detectors

asked Jul 9, 2017 at 13:20

16 votes

3 answers

2k views

Are the first order phase transitions always associated with a latent heat?

statistical-mechanics condensed-matter phase-transition ising-model critical-phenomena

asked Jul 27, 2017 at 19:00

16 votes

7 answers

5k views

Why the electrons below the Fermi level do not conduct electricity?

solid-state-physics electrons electric-current semiconductor-physics metals

asked Jan 28, 2017 at 15:08

15 votes

1 answer

2k views

QED and anomaly

quantum-field-theory quantum-electrodynamics unitarity quantum-anomalies ward-identity

asked Jul 19, 2015 at 14:59

15 votes

1 answer

3k views

Boosts are non-unitary!

quantum-field-theory special-relativity hilbert-space group-theory representation-theory

asked Feb 13, 2014 at 15:09

15 votes

2 answers

3k views

What is the orbital angular momentum (OAM) of individual photons?

quantum-field-theory optics photons angular-momentum quantum-optics

asked Feb 13, 2014 at 9:24

14 votes

1 answer

1k views

Localized field quanta?

quantum-field-theory fourier-transform klein-gordon-equation point-particles

asked Feb 11, 2014 at 12:32

14 votes

1 answer

14k views

Majorana mass vs Dirac Mass

quantum-field-theory particle-physics mass dirac-equation majorana-fermions

asked Mar 1, 2014 at 5:31

14 votes

1 answer

566 views

What are the minimal postulates to do quantum mechanics in path-integral formulation without knowing the operator formulation?

quantum-mechanics schroedinger-equation path-integral quantization

asked Jun 5, 2017 at 3:36

13 votes

2 answers

2k views

Does classical electrodynamics have $U(1)$ symmetry? If yes, how?

electromagnetism quantum-electrodynamics classical-electrodynamics gauge-invariance

asked Aug 19, 2017 at 7:48

13 votes

3 answers

562 views

Why do we take two different approaches to the "meaning of causality" in quantum mechanics and quantum field theory?

quantum-field-theory special-relativity causality

asked Sep 24, 2017 at 15:31

13 votes

2 answers

317 views

What is the physical implication(s) of the isomorphism between ${\rm SO}(2)$ and $\mathbb{R}/\mathbb{Z}$?

quantum-field-theory condensed-matter symmetry group-theory spacetime-dimensions

asked Jan 16, 2018 at 17:56

13 votes

6 answers

4k views

How do we prove that the 4-current $j^\mu$ transforms like $x^\mu$ under Lorentz transformation?

electromagnetism special-relativity vectors inertial-frames lorentz-symmetry

asked Mar 19, 2018 at 15:14

13 votes

4 answers

3k views

What would qualify as a deceleration rather than an acceleration if speed is unchanged?

kinematics acceleration terminology velocity vectors

asked May 4, 2018 at 10:13

13 votes

4 answers

3k views

Temperature of electroweak phase transition

cosmology electroweak baryogenesis leptogenesis thermal-field-theory

asked Dec 17, 2014 at 7:34

13 votes

6 answers

1k views

Charged particle as observed from an inertial and a non-inertial frame of reference

electromagnetism electromagnetic-radiation classical-electrodynamics equivalence-principle classical-field-theory

asked Oct 15, 2016 at 3:56

13 votes

3 answers

682 views

Why don't we have a "Cooper pair" of two holes in a superconductor?

quantum-field-theory condensed-matter superconductivity many-body

asked Oct 24, 2018 at 16:37

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781 Questions

Idea of Covering Group

Why does a system try to minimize its total energy?

Scattering, Perturbation and asymptotic states in LSZ reduction formula

Newton's law requires two initial conditions while the Taylor series requires infinite!

Self-adjoint and unbounded operators in QM

Relation between Wilsonian renormalization and Counterterm Renormalization

Symmetry Breaking And Phase transition

What is the conclusion from Aharonov-Bohm Effect?

What does a $\rm SU(2)$ isospin doublet really mean?

In what sense is the proper/effective action $\Gamma[\phi_c]$ a quantum-corrected classical action $S[\phi]$?

Constructing Lagrangian from the Hamiltonian

Does the number density of photons $n_\gamma\approx 10^8 \:\mathrm m^{-3}$ refer to CMB photons only?

Rest mass of phonon: is this concept definable?

Why is Higgs particle detected much later than top quark when it's lighter? [duplicate]

Are the first order phase transitions always associated with a latent heat?

Why the electrons below the Fermi level do not conduct electricity?

QED and anomaly

Boosts are non-unitary!

What is the orbital angular momentum (OAM) of individual photons?

Localized field quanta?

Majorana mass vs Dirac Mass

What are the minimal postulates to do quantum mechanics in path-integral formulation without knowing the operator formulation?

Does classical electrodynamics have $U(1)$ symmetry? If yes, how?

Why do we take two different approaches to the "meaning of causality" in quantum mechanics and quantum field theory?

What is the physical implication(s) of the isomorphism between ${\rm SO}(2)$ and $\mathbb{R}/\mathbb{Z}$?

How do we prove that the 4-current $j^\mu$ transforms like $x^\mu$ under Lorentz transformation?

What would qualify as a deceleration rather than an acceleration if speed is unchanged?

Temperature of electroweak phase transition

Charged particle as observed from an inertial and a non-inertial frame of reference

Why don't we have a "Cooper pair" of two holes in a superconductor?