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.

View More On Wikipedia.org
Recent contents Top users
  1. J

    Time Evolution of Spin in a Magnetic Field

    Homework Statement The Hamiltonian of a spin 1/2 particle is given by: $$H=g\overrightarrow { S }\cdot \overrightarrow { B } $$ where ##\overrightarrow { S }=\hbar \overrightarrow{\sigma }/2## is the spin operator and ##\overrightarrow { B }## is an external magnetic field. 1. Determine...
  2. J

    I Schrodinger equation and Heisenberg equation of motion

    My question is that how does the Schrodinger equation arise from the Heisenberg equation of motion in the quantum field formalism. These are from Hatfield's book. So I'm having some difficulties to reproduce (2.36) by plugging (2.55) into (2.37) primarily because H is an integral...
  3. C

    B Heisenberg applied to accelerated particles

    I may be getting these Thread Levels wrong. I get the impression that they apply to my level of knowledge such that someone else might be able to give an answer that I might be able to understand rather than the level of knowledge required to answer the question. Rest assured I am quite stupid...
  4. Sophrosyne

    B Measuring momentum and position in particle colliders

    When we look at those pictures of colliding particles in particle colliders, we see a large collection of curves and lines radiating out from the point of collision, representing the new particles which have been created. So two questions about this: 1) Why are these acting like particles in...
  5. victorhugo

    B Question about the Heisenberg U.P. & the Observer Effect

    I studied only half a semester of quantum physics in high school (which i only finished 8 months ago and came first in physics luckily) but i remember Heisenberg's uncertainty principle. All over youtube people were saying things like "this is God's way of keeping us from getting into perfection...
  6. S

    I How can the total orbital angular momentum be zero?

    I'm trying to understand the rotations of rigid diatomic molecules such as HCl. My understanding of the orbital angular momentum is that it is quantized with a total value equal to $$E=\frac{\hbar^2}{2I}J(J+1)$$ where I is the rotational moment of inertia and J is the quantum number. Also, J...
  7. Lunct

    I What are the units for the Heisenberg Uncertainty Principle?

    To my understanding(correct me if I am wrong), one consequence of the Heisenberg Uncertainty Principle is that energy levels can fluctuate by some amount, e, for a short time, t. As long as e x t does not exceed h/4pi (where h= Planck's constant). My quarry is that what are the units for the...
  8. Noora Alameri

    I Effect of Homog./Non-Homog. Magnetic Field in Heisenberg Spin System

    Hey, I have a simple question: What is the effect of the homogeneous and non-homogeneous static magnetic field in the Heisenberg spin system? Like what is so difference between the homogeneous and non-homogeneous magnetic field and what is the effects of the two cases in the spin system...
  9. W

    B Are vertical lines from squinting a Quantum phenomenon?

    When looking at a night light with almost closed eyes, I notice that the light becomes a vertical line. When tilting my head 90 degrees, the line becomes horizontal. Can this be explained by Heisenberg's Uncertainty principle? This question has been asked in another thread : "Squinting at...
  10. A

    Quantum mechanics - Heisenberg picture

    Homework Statement We consider the O2- molecule, with the Hamiltonian and position operator having matrix representations in terms of the Pauli matrices: In the Heisenberg picture, the position operator is: (1) Find the eigenvalues and eigenstates of x(t) at time t=pi*hbar/(4A) (2) The...
  11. victor94

    I What inspired Dirac's formulation of quantum theory?

    "historically the Heinsenberg equation of motion was first written by P. A. M Dirac, who - with his characteristic modesty- called it the Heinsenberg equation of motion." Modern quantum mechanics/ J.J. Sakurai, page 84 Why dirac did that?, I didn't find any source. Any information about this...
  12. B

    How Do Heisenberg Equations Describe Spin Dynamics in a Magnetic Field?

    Homework Statement Consider a spin ##\frac{1}{2}## particle at rest in a B-field ##\vec B = B_0\vec e_z##. (a) Find the Heisenberg equations for ##\hat S_x## and ##\hat S_y##. (b) Obtain from the Heisenberg equations two decoupled second-order differential equations for ##\langle \hat S_x...
  13. wolram

    B Scientists evade the Heisenberg uncertainty principle

    https://www.sciencedaily.com/releases/2017/03/170322143233.htmDate: March 22, 2017 Source: ICFO-The Institute of Photonic Sciences Summary: Researchers report the discovery of a new technique that could drastically improve the sensitivity of instruments such as magnetic resonance imagers (MRIs)...
  14. A. Neumaier

    I On the Heisenberg uncertainty relation

    Are there fundamental limits on the accuracy for measuring both position ##q## at time ##t## and momentum ##p## at time ##t+\Delta t##, with tiny ##\Delta t##? If yes, why? If no, why can't one then measure (in principle) both ##q## and ##p## arbitrarily well at the same time ##p## (which is...
  15. A

    A Difference between Hubbard and Heisenberg-model

    Hi, I read a chapter about the Heisenberg-model, and then something about the Hubbard-Model. The Heisenberg-model just shows, that neighbouring spins allign antiparallel if J<0. The Hubbard-Model says, that there is a hopping probability t and an Coulomb replsion, so that a material becomes...
  16. FallenApple

    Why did this professor have a suitcase full of cocaine?

    Sorry about the pun, I just couldn't resist." The amount of cocaine found in the bag Frampton was carrying was 1,980 grams. When asked why he’d been making this calculation, Frampton said: “My mind works in a strange way.”...
  17. M

    Setting up an Uncertainty Problem

    Homework Statement A proton is known to lie within the nucleus of a gold atom. The radius of a gold nucleus is approximately 6 fm. What is the minimum uncertainty in the proton’s velocity [you may treat the problem as one-dimensional and you should express your answer as a fraction of c]...
  18. dccd286

    B Does the Uncertainty Principle work through barriers?

    I'm currently designing an experiment on Double slits for a high school science fair, but I'm not sure whether it's plausible or not. I'll be spending some of my savings for this, that's why I would like to hear some feedback from more-knowledgeable people first. In this experiment, I am trying...
  19. C

    I Are we in a simulation and quantum tunneling?

    Preface: As I understand it, according to quantum mechanics, there is a very good probability that I am sitting right in my chair right now, typing this question out. However, there is a non-zero, ever so small probability, however infinitesimally small chance that I am somewhere else in the...
  20. Titan97

    Uncertainty in single slit diffraction

    Homework Statement An electron is moving in a parallel beam along the x-direction with momentum, p=mv. It encounters a slit of width w. Assuming that the electron gets diffracted somewhere within the central maximum of small angular magnitude Δθ, estimate the uncertainty Δp in its momentum...
  21. K

    Quantum Quantum Physics Books: Learn Heisenberg, Dirac, Pauli & More

    I'm really interested in quantum theory and would like to learn all that I can about it. I'm looking books for learning quantum physics that contains derivation of Heisenberg uncertainty principle, dirac notation, pauli matrices, quantum operators, hawking radiation, etc. What are good books to...
  22. C

    I Heisenberg Uncertainty Principle

    Hi all, I am 18 years old, and am looking to go into engineering, but I have a strong interest in theoretical physics. As such I have recently written a short research paper into the Heisenberg Uncertainty Principle, and I wondered if anyone would be willing to have a quick read and give me any...
  23. Q

    I Interpret Heisenberg Picture: Operators & States

    Can anybody give a natural interpretation of operators and states in the Heisenberg Picture? When I imagine particles flying through space, it seems that the properties of the particles are changing, rather than the position property itself. Is there any way I should be thinking about these...
  24. Madi Araly

    I Uncertainty Principle.... Intent Behind It?

    I've been pre-occupied with Heisenberg's uncertainty principle for around four years now, and I've come to fabricate a lot of questions. The most pressing one, however, is as follows: To me, the uncertainty principle seems to reference our (relatively) poorly controlled methods to measure a...
  25. L

    A Heisenberg ferromagnet -- Spontaneous symmetry breaking

    Heisenberg model of ferromagnet is defined by \hat{H}=-J \sum_{\langle i,j \rangle} \vec{S}_i \cdot \vec{S}_j where ##J>0## and summation is between nearest neighbours. Hamiltonian is perfectly rotational symmetric. However, the ground state “spontaneously” chooses a particular orientation...
  26. A. Neumaier

    I The Heisenberg cut demystified

    That doesn't follow. Selecting a system to study is necessary for most of physics. But it is always a subjective act - since Nature isn't divided into system and the rest of the universe. Most of the time we don't want to consider the universe as a whole but only the particles in a particular...
  27. entropy1

    B Thought experiment violates Heisenberg? (of course not)

    Suppose we have an elementary double-slit experiment: A laser fires individual photons through a double slit at a detectionscreen made of atoms. As we fire photons, an interference pattern emerges, exposing the momentum of the photons (the frequency of the laser). So, we have registration of...
  28. kq6up

    I Feynman Lecture Vol III Ch. 8 Question -- Heisenberg matrix picture

    Is the Hamiltonian matrix that is constructed in Ch 8 of the Feynman lectures the Heisenberg matrix picture, or is it something else? I am just curious. Thanks, Chris Maness
  29. atyy

    Can decoherence be formulated in the Heisenberg picture?

    In another thread, stevendaryl and I were trying to understand whether MWI can be formulated in the Heisenberg picture. Since neither of us really understands MWI, I tried to retreat to safer ground by asking: Can decoherence be formulated in the Heisenberg picture?
  30. zonde

    Photon energy in Heisenberg picture

    I would like to ask a quick (I suppose) question. Does a photon have definite energy in Heisenberg picture? My motivation for this question comes from reading that Hamitonian is generator of time evolution. But in Heisenberg picture time evolution is associated with operator not quantum system...
  31. Stephanus

    Determinism and Uncertainity Principle

    Dear PF Forum, Determinism. 1. Is there determinism? 2. Because we can't measure the electron position, it doesn't mean there's no determinism? Heisenberg uncertainity principle states, per wiki: But because we can't measure it, it doesn't mean that the universe itself is indeterministic...
  32. entropy1

    Difference/similarity between superposition and uncertainty

    What is the relation between "superposition" and "the Heisenberg uncertainty relation"?
  33. T

    Understanding proof for Heisenberg uncertainty

    I've uploaded a proof of the Heisenberg uncertainty principle from Konishi's QM. I just don't quite understand one part: what is the significance of the discriminant being less than or equal to 0? Wouldn't this just result in ## \alpha = R \pm iZ ##? Why would this be desired in this proof?
  34. D

    Instantaneous eigenstates in the Heisenberg picture

    I'm a bit confused as to what is meant by instantaneous eigenstates in the Heisenberg picture. Does it simply mean that if vectors in the corresponding Hilbert space are eigenstates of some operator, then they won't necessarily be so for all times ##t##, the eigenstates of the operator will...
  35. Zeeboozoo

    Tangibly Explaining HUP to General Chemistry Students

    I understand this topic has been brought up before, however there appears to be "truth" or "lies" and very little in between when it comes to explaining the Heisenberg Uncertainty Principle (HUP) to students of freshman chemistry. I'm teaching university general chemistry to students who've had...
  36. Multiple_Authors

    Does the Heisenberg Uncertainty Principle Imply Energy Nonconservation?

    Multiple_Authors submitted a new PF Insights post Does the Heisenberg Uncertainty Principle Imply Energy Nonconservation? Continue reading the Original PF Insights Post.
  37. K

    Ferromagnetic Heisenberg Model

    Now after applying and removal magnetic field H=0 there will be residual magnetic domain in XYZ directions Is the Heisenberg Model at very low temperature express about the energy of the system with higher accuracy than Ising Model in the previous case ? and at high temperature is the Ising...
  38. B

    Understanding Heisenberg's Principle: x and p instead of delta x and p

    Homework Statement I don't get how you can use x and p instead of delta x and p in Heisenberg's principle. Also why is it just h bar? Isn't it supposed to be h bar/2? Problem 2-iv Homework Equations delta x* delta p >= h bar/2 The Attempt at a Solution I tried to deal with this problem but I...
  39. ZapperZ

    Insights Misconception of the Heisenberg Uncertainty Principle - Comments

    ZapperZ submitted a new PF Insights post Misconception of the Heisenberg Uncertainty Principle Continue reading the Original PF Insights Post.
  40. L

    Heisenberg uncertainty question

    I read this article by Hawking which includes this quote " In classical mechanics one can predict the results of measuring both the position and the velocity of a particle. In quantum mechanics the uncertainty principle says that only one of these measurements can be predicted; the ob server can...
  41. F

    Heisenberg Uncertainty in wavelength and position

    Homework Statement Show that ## \Delta\lambda\Delta\ x>lamdba^2/4*pi## The Attempt at a Solution When I substitute de Broglie's p=h/lambda I get the equation of ##\frac {\Delta\x}{\Delta\lambda} > 1/(4*pi )##
  42. J

    Heisenberg Uncertainty Principle clarification

    I found these two examples in a books which demonstrate Heiseberg's uncertainty relation...
  43. J

    Heisenberg uncertainty principle calculations

    I am having some trouble understanding what to use for the uncertainties in the Heisenberg principle. My chemistry book has two problems on this principle. One asks to find the minimum uncertainty in the position of a marble of mass 1.0g given that its speed is known within +- 1.0 mm/s. The...
  44. A

    Minimum uncertainty of the momentum of a small particle

    Homework Statement Find the minimum uncertainty of the momentum of a small particle with mass m=1g, which is confined within a region of width a=1cm. Homework Equations Delta(p)*Delta(x)>=hbar/2 The Attempt at a Solution Delta(p)*Delta(x)=hbar/2 Delta(p)*10^(-2)=hbar/2 Delta(p)=10^2*hbar/2...
  45. S

    Interpretation of the Heisenberg picture in QM

    I was always a bit puzzled by the Heisenberg picture (not mathematically, I'm fine with that, but conceptually) - if a "state" describes a system, how can it not be time-dependent, if the system changes? I just found an alternative way of looking at it which seems to make sense to me, but I'm...
  46. J

    Heisenberg's Microscope Derive Exactly Uncertainty Principle

    Can the Heisenberg's Gamma Ray Microscope thought experiment derive the Uncertainty Principle precisely? Most derivations I find, the uncertainty is roughly 2h, whereas the uncertainty principle is "hbar over 2". Is there anywhere where there is more precise calculations to obtain "hbar over 2"...
  47. R

    Application of Heisenberg Uncertainty Principle

    Homework Statement A parallel beam of electrons traveling in x- direction falls on a slit of width d. If after passing the slit, an electron acquires momentum py in the y direction then for a majority of electrons passing through the slit A. |py|d ≈ h B. A. |py|d > h C. |py|d < h D. |py|d >> h...
  48. D

    Harmonic oscillator in Heisenberg picture

    For the harmonic oscillator in 1-D we get the 2nd time derivative of the x Heisenberg operator = -ω2 x. When that is integrated it gives xH (t) = Acos(ω t) +Bsin (ω t) where A and B are time independent operators. My question is why are the constants A and B incorporated into the terms as a...
  49. B

    Heisenberg equation of motion - field theory.

    Hi, I'm completely stuck with problem 3a). I have no idea of how to start. Anyone have any clue?http://speedy.sh/9JkCf/handin1-4.pdf
  50. C

    Interaction picture equation from Heisenberg equation

    The standard Heisenberg picture equation of motion is $$i\hbar\frac d{dt}A_H=[A_H,H],$$ assuming no explicit ##t##-dependence on the Heisenberg-picture operator ##A_H##. I've been trying to go directly from this equation to the corresponding interaction-picture equation, $$i\hbar\frac...
Back
Top