What is Heisenberg: Definition and 308 Discussions

Werner Karl Heisenberg (; German pronunciation: [ˈvɛɐ̯nɐ ˈhaɪzn̩ˌbɛɐ̯k] (listen); 5 December 1901 – 1 February 1976) was a German theoretical physicist and one of the key pioneers of quantum mechanics. He published his work in 1925 in a breakthrough paper. In the subsequent series of papers with Max Born and Pascual Jordan, during the same year, this matrix formulation of quantum mechanics was substantially elaborated. He is known for the uncertainty principle, which he published in 1927. Heisenberg was awarded the 1932 Nobel Prize in Physics "for the creation of quantum mechanics".Heisenberg also made important contributions to the theories of the hydrodynamics of turbulent flows, the atomic nucleus, ferromagnetism, cosmic rays, and subatomic particles. He was a principal scientist in the German nuclear weapons program during World War II. He was also instrumental in planning the first West German nuclear reactor at Karlsruhe, together with a research reactor in Munich, in 1957.
Following World War II, he was appointed director of the Kaiser Wilhelm Institute for Physics, which soon thereafter was renamed the Max Planck Institute for Physics. He was director of the institute until it was moved to Munich in 1958. He then became director of the Max Planck Institute for Physics and Astrophysics from 1960 to 1970.
Heisenberg was also president of the German Research Council, chairman of the Commission for Atomic Physics, chairman of the Nuclear Physics Working Group, and president of the Alexander von Humboldt Foundation.

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  1. Amaterasu21

    Momentum conservation, the double slit and Heisenberg

    One thing that's been troubling me lately is the idea that a quantum experiment can start with the same initial conditions, but the outcome is probabilistic, not deterministic, and how this fits in with the conservation of momentum. I was thinking about the classic double-slit experiment, in...
  2. C

    Heisenberg Equation: Solving the Poisson Brackets

    Hello when I try to go form the Schrödinger picture to the Heisenberg picture I get this equality : \begin{align} {d \over dt} A(t) = {i \over \hbar} H e^{iHt / \hbar} A e^{-iHt / \hbar} + e^{iHt / \hbar} \left(\frac{d A}{d t}\right) e^{-iHt / \hbar} + {i \over \hbar} e^{iHt / \hbar} A \cdot...
  3. O

    A very basic question about Heisenberg Uncertainty

    So I understand that Heisenberg Uncertainty states that we cannot know the position and velocity of an electron at the same time. Although I haven't go through its proof and assumptions, I have read on couple place that that's because if we are able to observe it, that means it have to reflect...
  4. Breo

    Heisenberg Picture Formalism: Rewriting Operators in Covariance

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  5. A

    Time Energy Uncertainty Question

    I would appreciate if someone could help figure out this thought experiment: Lets say I have two detectors named A and B. They both want to detect system C. For my naming convention I will say that C.B is the perturbed state of C after interacting with B Ok so both A and B decide to measure...
  6. A

    $100+ billion dollar gravity business

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  7. 2

    Trouble with Hermitian operators?

    I am looking at the derivation of the Heisenberg Uncertainty Principle presented here: http://socrates.berkeley.edu/~jemoore/p137a/uncertaintynotes.pdf and am confused about line (21)... I do not understand why AB and BA are complex conjugates of each other... (I'm still in high school so I...
  8. B

    Path Integral From Heisenberg Uncertainty?

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  9. P

    Heisenberg's Matrix Mechanics: An Understanding Review

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  10. R

    Basic Heisenberg uncertainty principle stuff

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  11. F

    2 questions--seems simple -- Heisenberg Uncertainty

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  12. M

    SU(3)-invariant Heisenberg XXX chain

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  13. S

    Formula of Heisenberg Uncertainty

    I came across two different forms of Heisenberg uncertainty: \Delta x . \Delta p \geq \frac{h}{2 \pi} and \Delta x . \Delta p \geq \frac{h}{4 \pi} and I read here in PF both forms are correct. I want to know how we apply both forms in solving problem. Here is the example: 1. An electron...
  14. P

    That Heisenberg Uncertainity Principle

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  15. L

    Heisenberg momentum uncertainty

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  16. J

    Hamilton's equation from heisenberg equation of motion

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  17. M

    SU(2) operators to SU(N) generators for Heisenberg XXX

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  18. Q

    Heisenberg Uncertainty due to interaction of the inherent reality?

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  19. atyy

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  20. pellman

    Heisenberg equation of motion for the Dirac field?

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  21. H

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  22. D

    How does Weinberg's Quantum Theory of Fields develop QFT in Heisenberg picture?

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  23. I

    Books that emphasize Heisenberg picture

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  24. K

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  25. D

    The uncertainty operator and Heisenberg

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  26. T

    Does Heisenberg apply to a collapsed wavefunction?

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  27. A

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  28. L

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  29. H

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  30. S

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  31. Q

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  32. D

    Solutions of Heisenberg Equations of Motion for Angular Momenta

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  33. S

    Ground State Degeneracy in ferromagnetic Heisenberg model

    I am reading the book "Lecture notes on Electron Correlation and Magnetism" by Patrik Fazekas. It says, "The ground state (of Heisenberg FM model) is not unique. We have just found that the system has the maximum value of the total spin Stot = LS. Sztot = LS state which is maximally...
  34. snoopies622

    How to go from Heisenberg operators to Schrödinger operators

    It is obvious to me how \hat {x} = x; \hspace{5 mm} \hat {p}_x = -i \hbar \frac {\partial} {\partial x} implies [ \hat {x} , \hat {p}_x ] = i \hbar and I can accept that these two formulations are mathematically equivalent, but I do not know how in general (or even in this specific...
  35. G

    Heisenberg uncertainty principle and wavelength of light

    I read somewhere that Heisenberg described his uncertainty principle by saying that you can't measure position more accurately than the wavelength of light (which makes sense), so Δx > λ. This is what I don't get. He then says that p=h/λ, so Δp > h/λ2 Δλ. He the multiplies and sets Δλ ≈ λ to...
  36. A

    Understanding the Heisenberg Uncertainty Principle in Quantum Mechanics

    in quantum mechanics, these same pairs of variables are related by the Heisenberg uncertainty principle. The energy of a particle at a certain event is the negative of the derivative of the action along a trajectory of that particle ending at that event with respect to the time of the event...
  37. K

    Rigid Box Particle and Heisenberg Principle

    Homework Statement For the ground state of a particle in a rigid box, we have seen that the momentum has a definite magni- tude (h/2π)k but is equally likely to be in either direction. This means that the uncertainty in p is Δp≈ (h/2π)k. The uncertainty in position is Δx≈ a/2. Verify that...
  38. B

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    Hey guys, I saw a joke about this in the jokes thread. So I went to see what it is exactly. But the thing is I didn't understand it fully. Could anyone please simplify and comprehend to me? Also I saw that it's only for particles. What is the importance of this theory. I hope non complicated...
  39. M

    Classical and quantum Heisenberg model

    In quantum Heisenberg model \hat{H}=-J\sum_{\vec{n},\vec{m}}\hat{\vec{S}}_{\vec{n}}\cdot \hat{\vec{S}}_{\vec{m}} ##J## can be obtained from dispersion experiment. For large spin ##S## even classical Heisenberg model is good for description of Curie temperature for example. Is that with the same...
  40. L

    Amplitude's time dependence in Heisenberg representation

    A = \langle q_f(t) \mid q_i(t) \rangle = \langle q_{f,H} \mid e^{iH(t_0-t)} e^{-iH(t-t_0)} \mid q_{i,H} \rangle = \langle q_{f,H} \mid q_{i,H} \rangle This means that A is time-independent, and depends only on the reference point ##t_0##. How is it possibly? From Schoedinger picture it...
  41. D

    Heisenberg Uncertainty Maximum Lifetime of Photon

    Homework Statement In special conditions, it is possible to measure the energy of a gamma ray photon to 1 part in 10^15. For a photon energy of 50 keV, estimate the maximum lifetime that could be determined be a direct measurement of the spread of photon energy. Homework Equations...
  42. S

    Uncertainty about Heisenberg Uncertainty Principle

    I'm not certain as to the true meaning of the Heisenberg Uncertainty Principle, and wonder if anyone can provide insight. I understand that there is a reciprocal relation between the certainties as to the position and momentum of a particle such as an electron; the more precisely position is...
  43. 7

    On my way to Heisenberg uncert. princ.

    I did a Fourier transform of a gaussian function ##\scriptsize \mathcal{G}(k) = A \exp\left[-\frac{(k-k_0)^2}{2 {\sigma_k}^2}\right]## and derived a result ##\sigma_k \sigma_x = 1## which is the same they get on http://www4.ncsu.edu/~franzen/public_html/CH795Z/math/ft/gaussian.html. Here is a...
  44. P

    Implications of Heisenberg uncertainty principle

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  45. matt_crouch

    Calculate the spin wave dispersion relation for a ferromagnetic heisenberg model

    Homework Statement Calculate the spin wave dispersion relation Ek for the ferromagnetic Heisenberg model with jtot = 1/2 Assume a 1d square lattice and interactions of strength J between nearest neighbours and zero elsewhere Homework Equations H|k> = [E0 +2jtot\sum J(r)(1-Exp(ik.r) ]...
  46. B

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    Say you have a particle in a one-dimensional box of length L. The particle can only have momentum values of the form p_{n} = \frac{nh}{2L} according to the De Broglie standing wave condition. Now say I don't measure the position of the particle, but I know for certain that it is in the box...
  47. C

    Heisenberg picture manifests Lorentz invariance?

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  48. J

    Heisenberg interaction Hamiltonian for square lattice

    Hi, I just started self studying solid state and I'm having trouble figuring out what the hamiltonian for a square lattice would be when considering the Heisenberg interaction. I reformulated the dot product into 1/2( Si+Si+δ+ +Si+δ+S-- ) + SizSi+δz and use Siz = S-ai+ai Si+ =...
  49. A

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    Hello! I have a doubt about Heisenberg uncertainty principle. Suppose that a particle moves along x-axis with a given uncertainty in velocity. Can I say something about its motion along y-axis? Thanks
  50. B

    Heisenberg s uncertainity principle

    existence of protons, neutrons nd alpha particles in the nucleus.
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