What is Electron spin: Definition and 89 Discussions

In atomic physics, the electron magnetic moment, or more specifically the electron magnetic dipole moment, is the magnetic moment of an electron caused by its intrinsic properties of spin and electric charge. The value of the electron magnetic moment is approximately −9.284764×10−24 J/T. The electron magnetic moment has been measured to an accuracy of 7.6 parts in 1013.

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  1. J

    What exactly is electron spin?

    What exactly is electron spin?The thing is, I had read in some general books on QM that spin of an electron is a non-classical degree of freedom,i.e.,an intrinsic angular momentum it possesses, and that it is NOT to be confused with a physically spinning electron. But in my physics textbook, it...
  2. F

    Electron spin entanglements - time-energy uncertainty

    I've been watching Susskind's lectures on quantum mechanics and he mentions that the time taken for two electrons to entangle their spin is a function of their distance, which in itself determines the energy that is released when two electrons fall into a singlet state. Does anyone here know how...
  3. P

    Is electron spin a perpetual motion?

    suppose we do not excite it or depress it, will it perform spin forever?
  4. alemsalem

    What happens to electron spin under Lorentz transformation?

    When you start in the rest frame of the electron, the Spinor w(p = 0) = (1 0 0 0 ) represents a positive energy state with spin up in the Z direction u = (0, 0 0 1),, that is the spinor is an eigenspinor of the operator S . u, where S is a 4 dimensional operator (S0, S) after a Lorentz...
  5. D

    Electron Spin: 360 Degrees or 720? Understand the Difference

    I read this quote from an article and another like is is http://scienceblogs.com/principles/2010/07/electron_spin_for_toddlers.php "and we see that the half-angle appears with a rather interesting consequence. To see this consequence let’s consider a rotation of 360 degrees – 2...
  6. D

    Transformation of electron spin vectors and operators - a problem

    Homework Statement I am struggling to understand spin transformations and have used Sakurai's method of |new basis> = U |old basis> to change basis vectors and hence should have Sz' = Udagger Sz U to transform the operator. I thought this should give Sz' = Sy in the workings (see...
  7. A

    Electron spin - energy difference between split levels?

    I found the interaction energy U of an electron in an atom with orbital quantum number l=0 with a uniform 2.00-T magnetic field to be 1.159E-4 eV, now it asks what is the energy difference between the two split states? We have short 3-point quizzes each day before lecture just to make sure...
  8. S

    Measurement of two components of electron spin

    Quantum physics texts describe how it is impossible to measure S(z) and S(x) spin components of a single electron at the same time where z represents the z axis,etc. What would happen if you try to trick nature by using a correlated pair of electons, emitted from an ion, moving in opposite...
  9. D

    Parallel vs anti parallel electron spin

    Homework Statement a hydrogen atom with its electron in the ground state 1s orbital can have proton and electron spins that are either parallel or anti parallel. which is the lower configuration and why? treat the electron as orbiting the proton in a plane perpendicular to the spin of the...
  10. zonde

    Visualization of electron spin

    I have seen in this forum number of discussions about problems of spin visualization. I think the problem is that spin usually is visualized as rotating charged billiard ball. But this classical picture requires that this billiard ball after any time interval resembles itself just with...
  11. sweet springs

    Magnetic force applied to electron spin magnetic moment

    Hi The magnetic force applied to electron spin magnetic moment is interpreted by Lorentz force qvXB ? I do not think so. If not, we easily understand why magnetic force can work. Regards.
  12. M

    Does Hydrogen's one electron spin?

    Elements with multiple electrons seem to push themselves around the nucleus due to their polar resistance with other electrons.. So in theory, with no other electrons to push into, could hydrogen's one electron be stationary
  13. U

    QED: Electron Spin & Magnetic Moment - Questions & Answers

    Hi, I've been doing Quantum Electrodynamics,and I've just finished the third chapter of QED-the strange theory of light and matter,by Richard Feynman. I have just three questions in regard to this... 1. what does Feynman mean when he says that any electron or photon can be polarized...
  14. Q

    Question about Entanglement and electron spin

    I'm working on a research paper on Quantum Entanglement and came across something I don't understand. (I assume this goes here rather than in the homework forum because it applies to a topic rather than a problem. Sorry if I'm mistaken.) From what I've read, if two electrons are entangled, one...
  15. W

    Electron spin and magnetic permeability

    Well, This is my first post, I used to read topics here, time to make one! Consider we have an oscillating magnetic field acting on a paramagnetic material, would this cause the unpaired electrons to alter their spin with the same frequency ? If so, would this affect the magnetic...
  16. Z

    What is the formula for calculating rotation speed?

    In wiki under spin it says: "Electrons are spin-1⁄2 particles. These have only two possible spin angular momentum values, called spin-up and spin-down. The exact value in the z direction is +ħ/2 or −ħ/2. If this value arises as a result of the particles rotating the way a planet rotates, then...
  17. B

    Exploring Electron Spin in NMR

    Hi all! I only have a short question concerning nuclear magnetic resonance: the basic principle is that we apply an external magnetic field, the protons (the core of H^1) is split into two energy levels (depending on the alignment of its spin) and we can apply an external high-frequency pulse...
  18. M

    Enhanced electron spin lifetime

    I am developing a cathode for studying the microwave induced magnetic isotope effect (MIMIE) in electrolytic reactions. My premise is that a cationic species and an electron donated by a cathode can be considered as a "quasi-radical pair," and that resonant magnetic pumping of the quasi-radical...
  19. P

    Is Electron Spin Change Possible?

    Can electron spin change? If so how does this happen?
  20. D

    Electron spin resonance question

    Homework Statement This isn't exactly a homework question, but my lab partner and I came across a phenomena whilst doing an electron spin resonance experiment, and I was wondering if anyone could help explain it. The sample we found electron spin resonance for is...
  21. W

    Double Slit Experiment and Electron Spin

    Can anyone direct me to any version of the double-slit experiment which used only electrons with aligned spin axes? If you can't direct me to an experiment, can you postulate how or if the double-slit experiment might be different using such electrons? Thanks!
  22. F

    Electron spin in magnetic field

    Homework Statement An electron is an eigenstate of sz at time t = 0 (spin up). It is in a magnetic field \vec B = (B \sin \theta, 0,B\cos\theta). Find the probability of finding the electron with spin down at time t. Homework Equations U(t) = \exp \left( -i \mathcal{H}...
  23. S

    The Role of Microwave Radiation in Electron Spin Resonance

    Homework Statement An electron is in an applied magnetic field. This electron is then radiated with microwave radiation which is at the correct larmor frequency. Homework Equations 1) Does the electron absorb microwave radiation when the applied microwave radiation induces a spin flip...
  24. R

    Magnetic Moment, Electron Spin, Energy

    Homework Statement The PE of a magnetic moment in an external magnetic field is given by U = -u dot B. Calculate the difference in energy between the two possible orientations of an electron in a magnetic field B = .6k T Homework Equations The Attempt at a Solution I realize...
  25. R

    Atoms, molecule, electron spin and magnetic media

    I read much about atoms, molecules and electrons but still i am not able to get answers for my study towards magnetic media. Please help me with the following questions in anyway you can, i would be really really grateful as it is going to help me a lot with my study towards magnetic media...
  26. F

    Exploring the Role of Electron Spin in Quantum Mechanics

    QM texts explain electron spin as an intrinsic spin with intrinsic angular momentum of electron. And this theory predicts (or postdicts maybe?) splitting of silver or hydrogen atom or electron beams in Stern Gerlach experiments. a few questions: 1) intrinsic angular momentum with its...
  27. D

    How Would a Change in Electron Spin Alter the Identity of Noble Gases?

    Homework Statement Suppose that electrons had a spin number of \frac{3}{2} instead of \frac{1}{2} That is, they have ould magnetic spin states of S_{z} = \frac{-3}{2}\hbar , \frac{-1}{2}\hbar , \frac{+1}{2}\hbar , \frac{+3}{2}\hbar Which elements would be the "new" noble gases in this...
  28. D

    Is Electron Spin Just a Mathematical Concept?

    It is true that electrons don't actually "spin" on their own axes according to their intrinsic spin, but this trait is simply a mathematical entity, correct?
  29. M

    Classical analouge of electron spin ?

    If one uses the "classical radius of the electron" and the known total angular momentum of the electron, it is easy to calculate that a point on the equator of the electron is moving at about 137 times the speed of light How is this 137 arrived at ? Any formula or method to get to this...
  30. G

    Why/how electron spin conserved?

    I can see that conservation of angular momentum (at least in classical mechanics) can be derived from the fact that force and direction between particles are parallel. What about electron spin? Does it count as momentum? Is it conserved in processes? If so, does one have to postulate this?
  31. R

    Electron Spin State and Values

    [SOLVED] Electron Spin State and Values Homework Statement An electron is in the spin state: X = A\begin{pmatrix} 1-2i \\ 2 \end{pmatrix} (a) Determine the constant A by normalizing X (b) If you measured S_{z} on this electron, what values could you get, and what is the probability...
  32. B

    Finding the Magnetic Field Gradient for the Stern Gerlach Experiment

    Homework Statement the force on a magnetic moment with z component u(z) moving in an inhomogenous magnetic field is given by Equation 7-51: F(z)=u(z)*(dB/dz). If the silver atoms in the stern gerlach experiment traveled horizontally 1 meter through the magnet and 1 meter in a field free...
  33. S

    Electron spin, why do the pairs have to be opposite?

    In the experiment where there are two electrons, and one is shot out to a person, the experiment depends on the two having opposite spins, one up one down, though which has which is not determined until observation. So person 1 looks at theirs and sees it's an upward spin. This collapses...
  34. A

    What is electron spin and intrinsic spin of elementary particles?

    What exactly is electron spin and intrinsic spin of elementary particles.Any link teaching these concepts from scratch would also be appreciated . Thnx
  35. S

    Electron Spin 'technicality' of sorts

    I can't really find the section to put this in, it has to do with Chemistry .. but . really.. Quantum Chemistry and like..well, doing quantum numbers my teacher asked whether or not the first electron in an orbital was + 1/2 or -1/2. When doing it on my own I always just write 1/2 , and then...
  36. J

    Electron spin and conservation of angular momentum

    Hi there, This is my first post here, although I have been haunting the forums for a few weeks :smile: I have a couple of questions regarding electron spin and conservation of angular momentum that have arisen from my research into the 'Einstein-de Haas' experiment. (Please bear with me...
  37. W

    Understanding Spin 2 Particles: Examples and Intuition

    We've all skipped a few undergraduate QM lectures, right? Right, and we all know how bad an idea that was, right? Right, so when the time comes and you wished you hadn't skipped those lectures, you probably don't have enough time to swim around in your misery for long, because in 48 hours...
  38. chroot

    Electron spin and chemical bonding

    I am relaying this question from rtharbaugh1, who originally posted it to a thread in the Quantum Physics forum: https://www.physicsforums.com/showthread.php?s=&postid=98040 Can any of you chemistry nerds answer this? :smile: - Warren
  39. Rockazella

    Permanent Magnets: Electron Spin & Magnetic Fields

    My physics teacher gave the class a brief explanation of a permanent magnet. If I understood him correctly he basically said the special condition with a permanent magnet is that all the electrons are circling uniformly (in same direction). The poles of the magnet are based on the direction the...
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