Recent content by Arne

  1. Arne

    I 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

    I 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

    I 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

    I 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

    I 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

    I 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

    I 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

    I 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
  10. Arne

    I Z2 symmetry in the hydrogen molecule when mapping to qubits

    Hello! When using a Jordan-Wigner-mapping or parity-mapping to map the hydrogen molecule \mathrm{H}_2 with two electrons and 4 spin-orbitals to 4 qubits, it is possible to reduce the number of qubits down to two [1,2,3]. The reason is apparently that the molecule has a discrete...
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