User DanielC

17 votes

Is there a classical explanation of why the electron in the ground state of a hydrogen atom does not spiral into the proton?

answered Jun 18, 2021 at 10:46

10 votes

Accepted

Do spinors form a vector space?

answered May 16, 2021 at 15:09

10 votes

How do I construct the $SU(2)$ representation of the Lorentz Group using $SU(2)\times SU(2)\sim SO(3,1)$?

answered Sep 20, 2017 at 22:10

10 votes

Commutator expectation value in quantum mechanics

answered Oct 16, 2018 at 22:06

9 votes

Accepted

Creation and annihilation operators in the hydrogen atom

answered Feb 19, 2021 at 23:38

6 votes

Accepted

Time evolution operator in QM

answered Oct 15, 2018 at 20:39

6 votes

Rotation Group and Lorentz Group

answered Feb 17, 2014 at 19:04

6 votes

Accepted

Is the Maxwell Stress Tensor Coordinate Dependent?

answered Feb 16, 2014 at 23:25

6 votes

Do we $\textit{need}$ to use a torsion-less connection in General Relativity?

answered Oct 30, 2017 at 15:26

5 votes

Comprehensive book on group theory for physicists?

answered Sep 28, 2017 at 6:58

5 votes

Stone-von Neumann theorem

answered Jan 9, 2018 at 23:48

5 votes

Is there a natural operator that is canonically conjugate to the Hamiltonian?

answered Jan 10, 2018 at 23:42

5 votes

The Lie algebra of the Lorentz group is $su(2) \oplus su(2)$. Is there a similar relation for the algebra of the Poincare group?

answered Nov 1, 2017 at 22:13

5 votes

Accepted

Translation of Fock's original paper?

answered Apr 5, 2021 at 23:47

5 votes

Accepted

Purely discrete spectrum of a self-adjoint operator

answered May 19, 2021 at 2:06

5 votes

How to prove $(A|\Psi\rangle)^{\dagger}=\langle\Psi|A$ $ $?

answered Sep 18, 2021 at 18:33

5 votes

Accepted

Wightman quantum field - Interpretation

answered Nov 11, 2019 at 22:05

4 votes

Show that any proper homogeneous Lorentz transformation may be expressed as the product of a boost times a rotation

answered Oct 28, 2020 at 1:45

4 votes

What quantity commonly used in physics is measured in "millijoules per cubic radian"?

answered May 24, 2022 at 5:53

4 votes

Why the Pauli-Lubansky and momentum operator build an irreducible representation of Poincarè group?

answered Feb 15 at 12:20

4 votes

Accepted

The Heisenberg Uncertainty Principle and the 1D particle in a box

answered Mar 13, 2021 at 23:14

4 votes

Accepted

Isometry group of Minkowski Space

answered Nov 1, 2017 at 10:12

4 votes

Classical Dirac equation

answered Dec 1, 2017 at 9:34

4 votes

Momentum operator acting on a bound state doesn't return an eigenvalue although kinetic energy operator does. Why?

answered Dec 2, 2017 at 17:10

4 votes

Accepted

Finding the standard deviation of observable

answered Oct 6, 2017 at 8:21

4 votes

Accepted

Generalization of $F=mv\frac{dv}{dx}=\frac{m}{2}\frac{d}{dx}(v^2)$ to 3-dimensions in a compact notation

answered Sep 11, 2017 at 15:59

4 votes

Why does spin arise in non-relativistic quantum mechanics?

answered Jul 24, 2017 at 6:36

3 votes

How to get Hamiltonian of QED from lagrangian?

answered Feb 16, 2014 at 23:43

3 votes

Rigged Hilbert space and QM

answered Feb 6, 2017 at 13:46

3 votes

Hamilton equations from Poisson bracket's formulation

answered Dec 2, 2017 at 14:57

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154 Answers

Is there a classical explanation of why the electron in the ground state of a hydrogen atom does not spiral into the proton?

Do spinors form a vector space?

How do I construct the $SU(2)$ representation of the Lorentz Group using $SU(2)\times SU(2)\sim SO(3,1)$?

Commutator expectation value in quantum mechanics

Creation and annihilation operators in the hydrogen atom

Time evolution operator in QM

Rotation Group and Lorentz Group

Is the Maxwell Stress Tensor Coordinate Dependent?

Do we $\textit{need}$ to use a torsion-less connection in General Relativity?

Comprehensive book on group theory for physicists?

Stone-von Neumann theorem

Is there a natural operator that is canonically conjugate to the Hamiltonian?

The Lie algebra of the Lorentz group is $su(2) \oplus su(2)$. Is there a similar relation for the algebra of the Poincare group?

Translation of Fock's original paper?

Purely discrete spectrum of a self-adjoint operator

How to prove $(A|\Psi\rangle)^{\dagger}=\langle\Psi|A$ $ $?

Wightman quantum field - Interpretation

Show that any proper homogeneous Lorentz transformation may be expressed as the product of a boost times a rotation

What quantity commonly used in physics is measured in "millijoules per cubic radian"?

Why the Pauli-Lubansky and momentum operator build an irreducible representation of Poincarè group?

The Heisenberg Uncertainty Principle and the 1D particle in a box

Isometry group of Minkowski Space

Classical Dirac equation

Momentum operator acting on a bound state doesn't return an eigenvalue although kinetic energy operator does. Why?

Finding the standard deviation of observable

Generalization of $F=mv\frac{dv}{dx}=\frac{m}{2}\frac{d}{dx}(v^2)$ to 3-dimensions in a compact notation

Why does spin arise in non-relativistic quantum mechanics?

How to get Hamiltonian of QED from lagrangian?

Rigged Hilbert space and QM

Hamilton equations from Poisson bracket's formulation