20,003 reputation
3873
bio website mat.univie.ac.at/~neum
location Vienna, Austria
age
visits member for 3 years, 5 months
seen 15 mins ago

I am currently primarily active on Physics Overflow. Here I mainly respond to comments on my old postings, sometimes upon request by email, and sometimes because I happen to see an interesting question for which I know a quick but useful answer. Occasionally I also post purely mathematical questions.

Some physics material I wrote:

  • A theoretical physics FAQ
  • Classical and Quantum Mechanics via Lie algebras
  • Renormalization without infinities - an elementary tutorial
  • Classical and quantum field aspects of light
  • Optical models for quantum mechanics
  • Molecular modeling of proteins and mathematical prediction of protein structure


  • 16m
    answered Rest Mass and Wigner's Classification
    Jul
    25
    comment Local Lorentz invariance or local Poincaré invariance?
    another, nice answer is at physicsoverflow.org/10794
    Jul
    25
    comment Lie algebra and Lie group about quantum harmonic oscillator
    My short and concise answer is at physicsoverflow.org/14831
    Jul
    25
    answered What is the defintion of a current-current diagram?
    Jul
    25
    answered In QFT are fields considered a property/function of spacetime? How do they become “excited”?
    Jul
    22
    comment Classical and quantum probabilities in density matrices
    See also my answer at physicsoverflow.org/14499
    Jul
    22
    comment Why is $\vert \phi \vert ^2$ infinite in QFT?
    I gave an answer at physicsoverflow.org/10759
    Jul
    22
    comment One question about Weinberg's derivation of arbitrary spin fields expressions
    I gave an answer at physicsoverflow.org/14842
    Jul
    22
    revised What is the entropy of a mixed state in classical physics?
    added 76 characters in body
    Jul
    21
    comment What is the entropy of a mixed state in classical physics?
    @Yrogirg: I added to my answer a caveat concerning my proposed formula.
    Jul
    21
    revised What is the entropy of a mixed state in classical physics?
    added qualification
    Jul
    21
    comment Geometric interpretation of perturbation theory in quantum field theory
    I gave another answer at physicsoverflow.org/10272
    Jul
    21
    comment Statistical analysis of data in Physics
    @vzn: I augmented my answer. You can specialize it yourself to casting dice, with the unreasonable prior being a Dirichlet prior with 100% probability for getting 6, weighted corresponding to 1000 events.
    Jul
    21
    revised Statistical analysis of data in Physics
    added an argument
    Jul
    20
    awarded  Necromancer
    Jul
    20
    awarded  thermodynamics
    Jul
    18
    comment Weinberg Volume I Equation (10.5.10) on page 451
    There is an answer at physicsoverflow.org/32575
    Jul
    18
    comment Principal value of 1/x and few questions about complex analysis in Peskin's QFT textbook
    another answer by Greg Graviton is at physicsoverflow.org/10327
    Jul
    18
    comment Introduction to AdS/CFT
    I had answered this on physicsoverflow.org/9884
    Jul
    18
    revised Statistical analysis of data in Physics
    added 4 characters in body