What is Stern-gerlach: Definition and 98 Discussions

The Stern–Gerlach experiment demonstrated that the spatial orientation of angular momentum is quantized. Thus an atomic-scale system was shown to have intrinsically quantum properties. In the original experiment, silver atoms were sent through a spatially varying magnetic field, which deflected them before they struck a detector screen, such as a glass slide. Particles with non-zero magnetic moment are deflected, due to the magnetic field gradient, from a straight path. The screen reveals discrete points of accumulation, rather than a continuous distribution, owing to their quantized spin. Historically, this experiment was decisive in convincing physicists of the reality of angular-momentum quantization in all atomic-scale systems.After its conception by Otto Stern in 1921, the experiment was first successfully conducted by Walther Gerlach in early 1922.

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  1. B

    Is Spin an Intrinsic Property of Electrons?

    Just a simple question: what happens to an electron beam in a S-G apparatus , does it split up in two spin-up/spin-down? if not, can you tell why? Thanks
  2. U

    Stern-Gerlach Inferometer (I don't understand the lecturer)

    Homework Statement This isn't exactly a homework question, but rather from the lecturer's slides. I'm not sure if I understand what's going on. Homework Equations The Attempt at a Solution Branch a is blocked 1. Atoms all with +ve spin enter 2. all the atoms can...
  3. M

    Stern-Gerlach experiment with orthogonal spin detector

    Suppose we have a Stern-Gerlach apparatus through which we send spin-1/2 particles and subsequently measure their position. If a passing particle "collapses" to the spin up state about X, it moves "up" and is registered by detector U, otherwise it "collapses" to the spin down state about X and...
  4. E

    Why Does the Lone Electron in Silver Have Zero Orbital Angular Momentum?

    "There are 47 electrons surrounding the silver atom nucleus, of which 46 form a closed inner core of total angular momentum zero – there is no orbital angular momentum, and the electrons with opposite spins pair off, so the total angular momentum is zero, and hence there is no magnetic moment...
  5. Telemachus

    Stern-Gerlach, polarized atom beam.

    Homework Statement In a Stern-Gerlach device, an atom beam with angular impulse J, travels through a magnetic field applied normally to the trajectory. The beam is separated in 2j+1 beams in general. Find the relative intensities for these beams if J=1 and if the beam is polarized with jθ=1 in...
  6. J

    Determing field gradient of Stern-Gerlach magnet

    Homework Statement Determine the field gradient of a 50-cm-long Stern-Gerlach magnet (d1) that would produce a 1-mm separation at the detector between spin-up and spin-down silver atoms that are emitted from an oven at T=1500. Assume the detector is located 50 cm from the magnet (d2). Note...
  7. N

    Stern-Gerlach Predictions of Elements

    I am baffled at the answers to the following HW quesitons compared with what I thought I knew about the topic. Hoping I can get my misunderstandings cleared up. Question 1 How many lines are expected on a detector plate of a Stern-Gerlach experiment if a beam of a) potassium atoms b)...
  8. alemsalem

    What's weird in the Stern-Gerlach experiment?

    The first thing is that it gets discrete spin states. Ok so we filter out a spin up state |+> and then send it through a perpendicular Apparatus then act surprised that we got |-> states back, isn't that what precession does? the only weird thing I can think of is that even after precession we...
  9. O

    Stern-Gerlach experiment when magnetic field varies from 0 to B

    Hello, in the Stern-Gerlach Experiment a beam of silver atoms passes through a magnetic field B and is separated in two beams Spin_Up and Spin_Down and a distance can be mesured between Up and Down My question is what happen B varies from 0 to Bmax ? Is the distance between Up and Down...
  10. Z

    Stern-Gerlach experiment with Gravitons

    It has long been predicted that gravitons will be spin 2. If that is true, then if we have a sufficient magnetic field, what is to stop us from recreating the Stern-Gerlach experiment and using a magnetic field to diffract them? Now, we have made very strong magnetic fields and to my...
  11. B

    Mechanics of Stern-Gerlach Experiments Question.

    In an SGY-SGZ experiment, where the magnetic field were placed along the y and z axis, we could write the equation: http://bit.ly/pSN1u2 for state of spin +Y, +Z, -Z respectively with the prob amplitudes a and b. take the bra \left\langle +Z\right| to the eq: http://bit.ly/qugX1b...
  12. F

    Spin Angular Momentum Conservation in the Stern-Gerlach Experiment

    I really did use the search function to try and figure this out for myself before posting :redface:, but this has been bugging me for approximately two days. I've been trying to understand the Stern-Gerlach experiment, primarily from hyperphysics (...
  13. R

    Are Stern-Gerlach Filters Modeled by Hermitian Operators in Quantum Mechanics?

    Can anyone help me with this simple question based on Feynman's Vol 3? Suppose I have a sequence of filters designed to show the suprising result that extra filters allow previously blocked photons, polarised light, spin one and spin one half particles etc. to get through. Then matrix...
  14. Fredrik

    The effect of the magnet in a Stern-Gerlach experiment

    A beam of silver atoms (which are electrically neutral spin-1/2 particles) enters an inhomogeneous magnetic field, and is split in two. The state of an atom that has passed the magnet is often described as |U>|↓>+|L>|↑>, where |U> and |L> are states that are localized to the upper and...
  15. LarryS

    Stern-Gerlach With 3 Magnets

    Richard Feynman describes a “modified Stern-Gerlach” experiment in which the apparatus consists of 3 magnets in a row, along the path of the beam. The first magnet is polarity “South on top, North on bottom”. The second magnet is twice as long as the first and of opposite polarity. The third...
  16. C

    Question about the Stern-Gerlach Experiment

    I have a general question about the Stern-Gerlach experiment. When a spin 1/2-particle passes through the magnets, is that effectively equivalent to applying a Hadamard transform to the state of the particle going through the apparatus? Also, let's say I wanted to create a quantum circuit...
  17. P

    Intrinsic spin stern-gerlach application

    find the following: if a particle (s=1/2) is prepared such that it is in the spin up state |f>=|z+> what do the following mean? [<f|(Sz - <z+|Sz|f>1)^2|f>]^½ and [<f|(Sx - <f|Sx|f>1)^2|f>]^½ The middle term sandwiched between the states is squared and the whole term being square...
  18. K

    What's the motivation of using silver atoms in the Stern-Gerlach experiment？

    Historically the experiment was performed on silver atoms, but what's the reason of using silver?
  19. S

    Experimental realization of Stern-Gerlach SGy filter

    I have been reviewing Sakurai's treatment of the SG experiment by analogy with polarized light, and I realized that I am not sure that I really understand how to construct in a laboratory the SG_{y} filter to produce and separate the \left|S_{y};\pm\right\rangle states that are analogous to...
  20. T

    History of the Taylor-Phipps version of the Stern-Gerlach experiment

    Hi, I'm at the tail end of writing an essay about the Stern-Gerlach experiment and I am wondering if anyone knows of any reliable sources that discuss the historical context of the Taylor-Phipps version of the Stern-Gerlach experiment using hydrogen. All of the sources that I find use the...
  21. P

    Where Can I Find Resources for Understanding Stern-Gerlach Experiment Math?

    Hi! I'm wondering if anyone knows any good resources to learn the math involved in describing atomic states and outcome probabilities in Stern-gerlach experiments. This is to help me with my coursework, but I can't find a single online quantum course or anything that deals expressly with...
  22. A

    Bundle of tiny randomly orientated magnets through a Stern-Gerlach app

    When I would send a bundle of tiny randomly orientated magnets through a Stern-Gerlach apparatus I don’t think I would expect the pattern as obtained with silver atoms, displaying two separated spots. So how exactly does the electron spin effect the path of the atoms in this experiment?
  23. B

    Calc. field gradient of Stern-Gerlach magnet

    Homework Statement From Townsend "Modern Approach to Quantum Mechanics", problem 1.1: "Determine the field gradient of a 50-cm long Stern-Gerlach magnet that would produce a 1 mm separation at the detector between spin-up and spin-down silver atoms that are emitted from an oven at T=1500K...
  24. S

    Sequential stern-gerlach experiment

    I'm just getting the basics of quantum mechanics and I had a question regarding a modification of the stern-gerlach experiment that I think might help me understand the superimposed eigen-states better. Could someone please clarify what one would expect in the following situation? Suppose we...
  25. Q

    Stern-Gerlach Separation Distance on Target Film

    I have a question in which we are instructed to find the separation distance between the two impact zones of Sodium atoms on a photographic plate: A magnet of length l= 0.15m and field gradient \nablaB= 9.0T/m over its full length is used in a Stern-Gerlach experiment. If a beam of Sodium...
  26. B

    Effect of changes in Stern-Gerlach fields

    In regard to the Stern-Gerlach experiment, what happens if the field starts out homogenous or very weak, and is slowly changed to the strong inhomogenous field described in the experiment? There are two versions of this, what might be called “transition period” question. One would be . . ...
  27. R

    How Does the Stern-Gerlach Experiment Illustrate Quantum Spin Measurement?

    Hi, I've been trying to understand the Stern-Gerlach experiment. I've been reading this book which explains how to find the amplitudes of measuring a particle to have a spin 1/2 lined up along some direction. Here is the book: http://www-thphys.physics.ox.ac.uk/people/JamesBinney/QBc6.pdf...
  28. M

    Another Stern-Gerlach Question

    As described in the Wikipedia article about the Stern-Gerlach experiment, if an electron passes through the (Z-axis oriented) device it will hit a screen on the other side in one of 2 possible locations, call them the upper and lower locations. Sometimes the electron is "spin up" about the...
  29. M

    Stern-Gerlach Question: Can Interference be Seen?

    Quoting from Wikipedia (Stern-Gerlach experiment): as the particles pass through the Stern-Gerlach device, they are "being observed." Is that true? For example let's say we have spin 1/2 particles, can you not create an appropriate double-slit (DS) setup on the other side of the...
  30. L

    Help Stern-Gerlach Experiment and Spherical Harmonics

    Hey, this is going to be abit long winded... In a Stern-Gerlach experiment a beam of hydrogenic atoms in the l=1 state traveling along the y-axis is first passed through an inhomogeneous magnetic field in the z-direction to yield three beams corresponding to three eigenstates Y(z,1), Y(z,0)...
  31. K

    Mixed States of Silver Atoms in a Stern-Gerlach Experiment

    Homework Statement In an experiment, we've isolated silver atoms that are in a purely |\uparrow \rangle state with respect to the z-axis, and feed these into a Stern-Gerlach apparatus oriented at an angle of \frac{\pi}{4} between the x and z axes, which measures an observable we will call...
  32. F

    Sequential Stern-Gerlach experiment to differentiate between two samples

    Homework Statement Compare the following situations (a) and (b): (a) A beam of atoms, half of which are preselected as “+ in z”, the other half as “− in z”, is sent through a Stern-Gerlach apparatus that ...(A) sorts in the z direction...
  33. R

    How Does Spin Orientation Affect Beam Intensity in a Stern-Gerlach Experiment?

    Homework Statement Consider a beam of spin-(1/2) particles passed through a Stern-Gerlach apparatus (+ve z orientation). The particles are in the ground-state of the Hamiltonian H = \frac{g\mu_{B}\hbar}{2} \left( ^{B_{z}}_{ B_{x} + iB_{y} }^{ B_{x} - iB_{y}}_{ - B_{z} } \right) and...
  34. S

    Stern-Gerlach Experimental Calculation

    I've run into a problem which has been bugging me for days. I know its related to the Stern-Gerlach experiment about firing hydrogen through an inhomogeneous magnetic field, but all i can do is give a vague qualitative description of the answers, and not an actual numerical one (because I don't...
  35. I

    How many traces observed in Stern-Gerlach?

    I am struggling with an Atoms and Nuclei past paper question, if someone can help please. In a Stern Gerlach experiment, how many traces on the plate would be observed if instead of hydrogen a)helium b)boron (atomic number 5), are used? [Hint: Boron will exist in 2L-S coupled states] I...
  36. E

    Why is the upper magnet in the Stern-Gerlach experiment wedge-shaped?

    Homework Statement http://en.wikipedia.org/wiki/Stern-Gerlach In the Stern-Gerlach experiment, is there a reason why the upper magnet is wedge-shaped and not flat? Homework Equations The Attempt at a Solution
  37. C

    Stern-Gerlach Probability: Find the Probability

    Homework Statement We're learning some basic quantum mechanics by studying the stern-gerlach experiment so some of my terminology might be a bit off as it might be particular to this book, I'm not sure. Say we have +z atoms (magnetic moment in +z direction?) shot through a +x selector...
  38. P

    Who Developed the Sequential Stern-Gerlach Apparatus and Formalism?

    Wondering who did the sequential Stern-Gerlach apparati experiments and who developed the ensuing formalism. If you could tell me the original paper sources without much trouble that would be great. Thanks.
  39. J

    Experimentally Verifying Photon Spin: Beyond Stern-Gerlach

    I just realized I don't know a simple thing. How do you experimentally verify, that photons are spin 1 particles? At least you cannot do it with the Stern-Gerlach experiment, because photons are not charged. The polarization effect is usually somewhat identified with the spin, but is it really...
  40. T

    The Spin-Up/Spin-Down Effect in the Stern-Gerlach Experiment

    A book that I've read says that there is no Stern-Gerlach experiment for electrons or protons because they carry electric charges and the Lorentz force will deflect them differently. But even if the Lorentz force deflect all of them upwards or downwards, won't they still separate slightly into...
  41. B

    What Is the Energy Difference in the Stern-Gerlach Experiment with Silver Atoms?

    OK I just have one more question haha. Question: Consider the original Stern-Gerlach experiment employing an atomic beam of silver, for which the magnetic moment is due entirely to the spin of the single valence electron of the silver atom. Assuming the magnetic field B has a magnitude 0.500...
  42. T

    How Does the Stern-Gerlach Experiment Reveal Quantum Angular Momentum?

    In a certain Stern-Gerlach experiment a bean of potassium atoms (mass: M=6.4673x10^-26 kg) emerges from an oven at a temperature of 150 C. That means that each potassium atom has a kinetic energy of 8.76x10^-21 J. The atoms pass through an inhomogeneous magnetic field, whose gradient is 1.2x10^2...
  43. T

    Why did Stern and Gerlach use a non-uniform magnetic field in their experiment?

    Why does the Stern-Gerlach experiment used non-uniform magnetic field? Why not a uniform magnetic field?
  44. CarlB

    Complex phases in Stern-Gerlach filters.

    I found an interesting way of calculating the complex phase changes induced by a series of Stern-Gerlach filters applied to a beam of spin-1/2 fermions. It's obvious enough that I'm sure someone else has seen it before, and I was hoping someone would give me a reference. A Stern-Gerlach...
  45. M

    How much would a hydrogen atom be deflected in the Stern-Gerlach experiment?

    In the stern-Gerlach experiment, how much would a hydrogen atom emanating from a 500 k oven (KE = 1.5kT) be deflected in traveling one meter throught a magnetic field whose rate of change is 10T/m? what is stern-gerlach?
  46. B

    Simple ftl setup using Stern-Gerlach

    Hi, I've been reading David Albert's book "Quantum Mechanics and Experience," and it got me thinking about how one could use Stern-Gerlach sorts of measurements on entangled electron pairs (or electron-positron pairs) to transmit a statistical signal from one to the other. Let's say you...
  47. C

    The magnetic field in Stern-Gerlach

    In the Stern-Gerlach experiement, what's so special about the magnetic field that causes the electrons to behave like they do? How would you explain this in layman terms? We learned that whenever a charged particle passes through a 'normal' magnetic field, a force F = qvB acts upon it, unlike...
  48. frankR

    Question about the Stern-Gerlach Expirement

    If Fz changes according to &muzdB/dz and the silver atoms are collimated into a beam how does the dipole magnetic moment of the atoms see and change in the B-field if the beam is cutting across the B-field perpendicularly? How does a changing B-field, in the verticle direction affect the Ag...
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