Recent content by Arne

  1. Arne

    Undergrad Assumptions about the convex hull of a closed path in a 4D space

    Hello everyone, I am struggling to get insight into a certain set in 4D space. Given is a closed path in 4D-space with constant Euclidean norm $$\vec{\gamma} (\theta):[0,2\pi]\to\mathbb{R}^4, \ \ \vec{\gamma}(0)=\vec{\gamma}(2\pi), \ \ ||\vec{\gamma}(\theta)||_2 = \mathrm{const.}$$ I am looking...
  2. Arne

    Undergrad Discrete Orthogonality Relations for Cosines

    Could you clarify how exactly you would like to use the convolution theorem? There is a version for Fourier coefficients https://en.wikipedia.org/wiki/Convolution_theorem#Convolution_theorem_for_Fourier_series_coefficients but I don't really see how this might help. Anyway, if you find you find...
  3. Arne

    Undergrad Parity Eigenstates: X Basis Explanation

    The section in the book is about the parity operator ##\Pi## which acts on the position basis as \Pi |x\rangle = |-x\rangle and with that also on the momentum eigenbasis \Pi |p\rangle = |-p\rangle The author then points out that the wavefunction in position or momentum space is mirrored under...
  4. Arne

    Undergrad Why does "control" mean "coherency" in Wigner's friend paradox?

    Dear Seyed, I'm sorry if my answers confuse you. I'm not sure how well your understanding in quantum mechanics is, so I tried to explain it as simple as possilbe, but as always in quantum mechanics, a simple explanation might actually be not very precise. For the sake of understanding, it might...
  5. Arne

    Undergrad Discrete Orthogonality Relations for Cosines

    It doesn't actually matter if we use limits j=0...N-1 or j=1...N since the functions are N-periodic and the j=0 term is exacly the same as the j=N term. But I usually find it conceptually easier to work with j=0...N-1.
  6. Arne

    Undergrad Why does "control" mean "coherency" in Wigner's friend paradox?

    Hello Seyed, It might be best to answer your questions in the opposite order. 2. First coherence/incoherence: In my argumentation above it might have been better to talk about pure states and mixed states. A pure state means that the state of the system is well defined. In contrast a mixed...
  7. Arne

    Undergrad Discrete Orthogonality Relations for Cosines

    Hello! We can verify the relations if we assume limits j=0...N-1. Then a sum of an exponential function can be evaluated with the geometric series \sum_{j=0}^{N-1} a^j = \frac{1 - a^N}{1-a} such that \sum_{j=0}^{N-1} \exp(\pm 2\pi i j k/N) = \sum_{j=0}^{N-1} (\exp(\pm 2\pi i k/N) )^j =...
  8. Arne

    Undergrad Why does "control" mean "coherency" in Wigner's friend paradox?

    Hello Seyed, I'm not an expert on this topic, so I might not explain this correctly, but I will try to give my view on your question. The state of the composite system is basically a Bell state. So to get this in a maybe more familiar form, I will replace |z+\rangle and |F_{z+}\rangle with...
  9. Arne

    Exploring Quantum Computation and Chemistry: A Master's Thesis Journey

    Hello! I'm a physics student, currently working on my master thesis. It is in the field of quantum computation and quantum chemistry. Nice to meet you all :) Arne