Larmor precession Definition and 16 Threads

  1. okaythanksbud

    I Does Larmor precession change the force exerted on a magnetic dipole?

    If we have a spinning spherical charge in a nonuniform magnet field that points in one direction (for simplicity lets say B=<0,0,k*z>). Since the magnetic field is nonuniform, there will be a force exerted on the dipole, F=(mu•∇)B=mu_z*k. So in this case we expect it to be constant. This is...
  2. D

    A Relationship between Larmor precession and energy eigenstates

    Quantum mechanically, a spin 1/2 particle in a uniform magnetic field has two energy eigenstates ##\ket{up}## and ##\ket{down}## and rotational degrees of freedom (distinct from the energy eigenstates) about the axis of the magnetic field. this can be derived from the Pauli matrix commonly...
  3. D

    I Larmor precession of an electron in a magnetic field?

    In QFT where the electromagnetic field is mediated by virtual photons, is it possible to describe the larmor precession of an electron as a series of emission and absorption of virtual photons? how does the spin angular momentum "evolve" over a series of events? This feels like a challenging...
  4. H

    Larmor Precession and a bar magnet

    As stated in the link below, when a magnet bar (or a current loop) is placed in an external magnetic field it (its magnetic moment) becomes aligned with the magnetic field while an orbiting electron would have precession with Larmor frequency. What is the reason for these different behaviors...
  5. Benhur

    How Do I Create the State Vector χ for Larmor Precession in a 2D B-field?

    I just tried to find the eigenvalues (for the energy), obtaining E = ±(γħ.√(Bo² + Γo²))/2 and the corresponding eigenvectors for the H matrix. But I don't know what to do to create de state vector χ.
  6. Bobs

    Quantum version of Larmor precession

    Homework Statement Homework Equations I didn't get what this actually means. The Attempt at a Solution I'm not sure whether it is correct. Could you take a look? Regards!
  7. fisher garry

    Deriving Larmor frequency problem

    I don't get how they get Eq. 5. Why is the direction of ##\mu## going outwards from the direction of B? And why does the fact that ##\frac{d\mu}{dt}## is perpendicular to both ##\mu## and ##B## mean that ##\mu## goes in circle?
  8. E

    I Moment and the Larmor precession

    Hi, In the Larmor precession, we tend to define the magnetic moment as the current multiplied by the surface (for an electron rotating around a nucleus), sometimes this moment is defined (generally) as the sum of the vectoriel products of half of the position vector and the charge times the...
  9. Twigg

    I Where Does Larmor Precession Occur?

    I have been doing a lot of exercises out of Griffiths lately, and one thing I spent a lot of time thinking about was Larmor precession. It's a fun thing to work out, but where does it actually happen? I'm having a hard time to see where it would apply. The first condition for Larmor precession...
  10. DeathbyGreen

    Larmor precession and magnetic ordering

    Homework Statement When we speak about Larmor precession we refer to atomic magnetic moments precessing in a magnetic field. In ordered magnets, such as ferromagnets, I never hear about larmor precession anymore. Are the magnetic moments frozen due to interactions with the surrounding crystal...
  11. kmm

    Why does Larmor precession appear to go against the right hand rule?

    For some reason, I don't understand the direction of larmor precession. Torque is: \mathbf{\Gamma} = \frac{d \mathbf{L}}{d t} = \mathbf{r} \times \mathbf{F} As an example, I understand with a gyroscope, using the right hand rule and with angular momentum in the direction as shown in this...
  12. A

    Kinetic Energy in Classical treatment of Larmor Precession

    This question pertains to the classical treatment of Larmor precession.I don't know whether to put it in the Classical Physics forum or this so I am putting it here. In the treatment we assume that the potential energy of the dipole-magnetic field system remains constant because there is no...
  13. H

    Larmor precession pi/2 out of phase

    Homework Statement I was going over the solution where it says \s_x, s_y are out of phase by pi/2. They first wrote equation of motion for \s_x, s_y and then did something to the matrix and now the have equation of motion for \s_+, s_- They rewrite \s_x, s_y in terms of \s_+, s_- to see that...
  14. L

    Spin dynamics and Larmor precession

    Homework Statement Consider an electron with spin, which should be in a homogenous magnetic field B=B0ez. This situation is described by the Hamiltonian of the shape \hat{H}=g\frac{\mu_B}{\hbar}\textbf{BS}. Consider now the time dependent state |\psi(t)> of the electron in spin space. The...
  15. R

    Larmor Precession and Force on a Magnetic Dipole

    Homework Statement I have two questions. Both involve derivations from textbooks, not end-of-the-chapter problems. The two textbooks are Quantum Mechanics by Griffiths, and A Modern Approach to Quantum Mechanics by John Townsend. My first question is about the discussion of Larmor...
  16. B

    Larmor Precession: Understand Charge Orbitting Fixed Charge

    i'm familiar with terminology used to denote rates of change in inertial and rotational frames, and the equation that links the two quantities, but working through a derivation/thought experiment to describe charge orbitting around another fixed charge in a weak magnetic field, it results in...
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