User Lopey Tall

8 votes

1 answer

728 views

General relativity as a gauge theory of the Poincaré algebra

asked Feb 10, 2020 at 12:36

6 votes

2 answers

827 views

Bertrand's theorem and nearly-circular motion in a Yukawa potential

homework-and-exercises forces classical-mechanics orbital-motion potential-energy

asked Jul 26, 2020 at 18:47

5 votes

2 answers

236 views

Inönü-Wigner contraction of Poincaré $\oplus$ $\mathfrak{u}$(1)

special-relativity group-theory lie-algebra poincare-symmetry galilean-relativity

asked May 16, 2020 at 10:47

2 votes

1 answer

667 views

Going from the Dirac Lagrangian to the adjoint Dirac equation

dirac-equation dirac-matrices clifford-algebra

asked Mar 9, 2020 at 22:41

2 votes

0 answers

414 views

Gamma matrices and the metric

metric-tensor dirac-matrices

asked Mar 27, 2020 at 11:14

2 votes

1 answer

131 views

Dirac delta, Fourier transform & exponentials

fourier-transform integration dirac-delta-distributions

asked Feb 17, 2020 at 16:07

2 votes

1 answer

789 views

Wedge product, tensor product, and Levi-Civita tensor/symbol

general-relativity metric-tensor tensor-calculus

asked Aug 13, 2019 at 21:47

2 votes

0 answers

110 views

Gravity from algebra

gravity resource-recommendations gauge-theory poincare-symmetry

asked Oct 30, 2018 at 14:25

2 votes

2 answers

3k views

Finding the expression for probability density (the Klein Gordon equation)

special-relativity field-theory probability density klein-gordon-equation

asked Feb 5, 2019 at 2:18

2 votes

1 answer

290 views

Hamiltonian of charged particle in an EM field and magnetic field does no work on charged particles

electromagnetism classical-mechanics magnetic-fields hamiltonian-formalism hamiltonian

asked Jul 31, 2020 at 15:44

2 votes

1 answer

158 views

Use of a geometric series sum in derivation of Bose-Einstein distribution

thermodynamics statistical-mechanics partition-function bosons chemical-potential

asked Aug 28, 2020 at 16:22

2 votes

1 answer

260 views

Physical interpretation of total derivative

newtonian-mechanics energy work differentiation

asked Jul 12, 2020 at 16:08

2 votes

2 answers

293 views

Does "adding a constant to the potential energy" imply "adding a total time derivative to the Lagrangian."

classical-mechanics lagrangian-formalism potential-energy conventions

asked Jul 14, 2020 at 22:10

2 votes

1 answer

168 views

Is Goldstein's matrix formalism to Hamiltonian mechanics necessary? [closed]

homework-and-exercises classical-mechanics lagrangian-formalism hamiltonian-formalism differentiation

asked Jul 24, 2020 at 17:11

2 votes

1 answer

253 views

Plane pendulum at an angle (Goldstein 12.11) [closed]

homework-and-exercises classical-mechanics hamiltonian-formalism adiabatic

asked Nov 15, 2020 at 14:09

2 votes

1 answer

173 views

Field theory Euler-Lagrange problem term

homework-and-exercises classical-mechanics lagrangian-formalism variational-calculus classical-field-theory

asked Nov 23, 2020 at 0:08

1 vote

1 answer

140 views

Scalar fields and spinors in 0+1D

spacetime field-theory dirac-equation spacetime-dimensions klein-gordon-equation

asked Aug 9, 2020 at 17:36

1 vote

0 answers

70 views

Generalizing creation and annihilation operators to multiple field Lagrangian

quantum-mechanics quantum-field-theory fourier-transform commutator

asked Feb 27, 2020 at 14:37

1 vote

1 answer

205 views

Spectral density of fluctuations (white noise/delta-correlated process)

statistical-mechanics correlation-functions noise fluctuation-dissipation

asked Nov 14, 2020 at 20:14

1 vote

1 answer

72 views

Hit rate of molecules on a wall

thermodynamics statistical-mechanics gas density-of-states

asked Jan 19, 2021 at 23:33

1 vote

0 answers

50 views

How do the radius and the center of the circular orbits of a particle depend on an adiabatically changing $B$ field [closed]

homework-and-exercises classical-mechanics magnetic-fields orbital-motion invariants

asked Jan 20, 2021 at 19:03

1 vote

1 answer

48 views

Properly accounting for indistinguishability of (homonuclear) diatomic molecules in "internal" partition function

statistical-mechanics molecules partition-function degrees-of-freedom identical-particles

asked Jan 25, 2021 at 13:50

1 vote

1 answer

92 views

Underdetermined system of equations for infinite parallel plates?

electrostatics electric-fields potential voltage capacitance

asked Feb 16, 2021 at 21:39

1 vote

1 answer

213 views

2-body problem, conservative central force, spherical symmetry, conversation of angular momentum, motion in a plane

classical-mechanics angular-momentum symmetry orbital-motion vectors

asked Jul 22, 2020 at 0:47

1 vote

1 answer

248 views

Deviations from purely circular orbit for an object in a Yukawa potential

homework-and-exercises newtonian-mechanics classical-mechanics orbital-motion

asked Jul 24, 2020 at 0:30

1 vote

2 answers

140 views

Validity of a differing frame of reference than that used in Landau and Lifshitz's solution [closed]

classical-mechanics reference-frames

asked Jul 12, 2020 at 17:59

1 vote

2 answers

132 views

Euler-Lagrange partial with respect to $r$ of a dot product involing velocity and a vector potential [closed]

homework-and-exercises electromagnetism classical-mechanics lagrangian-formalism variational-calculus

asked Jul 30, 2020 at 21:34

1 vote

1 answer

110 views

Reference request for Lie algebras

general-relativity resource-recommendations lie-algebra poincare-symmetry galilean-relativity

asked Apr 20, 2019 at 19:30

1 vote

0 answers

68 views

Error with generators of Lorentz group (basis of Lorentz Lie algebra) [closed]

homework-and-exercises special-relativity group-theory lorentz-symmetry lie-algebra

asked Apr 27, 2019 at 23:10

1 vote

0 answers

59 views

Entropy and observers

cosmology entropy universe observers

asked Nov 30, 2018 at 21:00

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76 Questions

General relativity as a gauge theory of the Poincaré algebra

Bertrand's theorem and nearly-circular motion in a Yukawa potential

Inönü-Wigner contraction of Poincaré $\oplus$ $\mathfrak{u}$(1)

Going from the Dirac Lagrangian to the adjoint Dirac equation

Gamma matrices and the metric

Dirac delta, Fourier transform & exponentials

Wedge product, tensor product, and Levi-Civita tensor/symbol

Gravity from algebra

Finding the expression for probability density (the Klein Gordon equation)

Hamiltonian of charged particle in an EM field and magnetic field does no work on charged particles

Use of a geometric series sum in derivation of Bose-Einstein distribution

Physical interpretation of total derivative

Does "adding a constant to the potential energy" imply "adding a total time derivative to the Lagrangian."

Is Goldstein's matrix formalism to Hamiltonian mechanics necessary? [closed]

Plane pendulum at an angle (Goldstein 12.11) [closed]

Field theory Euler-Lagrange problem term

Scalar fields and spinors in 0+1D

Generalizing creation and annihilation operators to multiple field Lagrangian

Spectral density of fluctuations (white noise/delta-correlated process)

Hit rate of molecules on a wall

How do the radius and the center of the circular orbits of a particle depend on an adiabatically changing $B$ field [closed]

Properly accounting for indistinguishability of (homonuclear) diatomic molecules in "internal" partition function

Underdetermined system of equations for infinite parallel plates?

2-body problem, conservative central force, spherical symmetry, conversation of angular momentum, motion in a plane

Deviations from purely circular orbit for an object in a Yukawa potential

Validity of a differing frame of reference than that used in Landau and Lifshitz's solution [closed]

Euler-Lagrange partial with respect to $r$ of a dot product involing velocity and a vector potential [closed]

Reference request for Lie algebras

Error with generators of Lorentz group (basis of Lorentz Lie algebra) [closed]

Entropy and observers