What is Stern gerlach: Definition and 42 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. Rayan

    Sequential Stern Gerlech experiment

    So I thought that when the $m_l = 1$ beam passes through the second SG-magnet, it should split into 3 different beams with equal probability corresponding to $ m_l = -1 , 0 , 1 $ since the field here is aligned along z-axis and hence independent of the x-axis splitting. And I thought that the...
  2. A

    I Measuring electron spin and measuring entangled electron spin

    Hi people, Lets assume, we have a stern gerlach setup and we are going to measure an atom's last orbit electron's spin with 60 degree from vertical axis. Therefore, in this case, our outcomes would be 3/4 for spin up, 1/4 for spin down. Let's assume, we have the same setup but we are going to...
  3. patric44

    Why the Stern-Gerlach experiment didn't detect the L?

    i recently read about the stern-gerlach experiment and found out that they did it in the first place to verify the principle of the "space quantization " introduced by Bohr , and they thought they did detect the quantization of the orbital angular momentum of ( L = 1 , m = 1,-1 ) neglecting the...
  4. Quarky nerd

    B Entangled electrons in the Stern-Gerlach experiment?

    I have always been interested in entagled electrons. so I thought about the stern gerlack experiment and simly wondered what would happen to entagled electrons in such an experiment. (although the prefix says high school i am able to appreciate more complicated answers).
  5. HastiM

    Stern Gerlach Experiment: How wide are the peaks?

    Consider the Stern Gerlach experiment, where the oven has a temperature such that the most probable velocity of the silver atoms is 750 m/s. The atoms are collimated by two slits of 0.03 mm width. The magnetic field has a strength of 1 T, a gradient of 5 T/cm, and the length of the magnet is...
  6. F

    I What causes the formation of multiple sub-beams in the Stern Gerlach Experiment?

    Hello Everyone, I am reviewing the SG experiment. I think the experiment was set out to demonstrate that the orbital angular momentum ##L## is quantized producing a quantized magnetic momentum. But silver and hydrogen atoms have no net orbital angular momentum. Still two sub-beams, due to two...
  7. grandpa2390

    Determine Field Gradient of a Stern Gerlach Magnet....

    Homework Statement Here is the Problem. I have the Solution but am having trouble understanding parts of it. 1.1. Determine the field gradient of a 50-em-long Stem-Gerlach magnet that would produce a 1-mm separation at the detector between spin-up and spin-down silver atoms that are emitted...
  8. CassiopeiaA

    B Conservation of Total Spin in the Stern Gerlach Experiment

    I just started reading Stern Gerlach Experiment and this thought crossed my mind. Totally a hypothetical question. If I pass an electron and positron through separate SG apparatuses, I will know in which spin state each particle has collapsed. But afterwords I let electron-positron pair...
  9. K

    I Measuring Spin in the Stern Gerlach Experiment

    When we are measuring the spin of the electron in the experiment, we choose the spin property as its eigen state for the measurement. The eigen vectors corresponding to these states could be time dependent. Can we still break the problem into solving time independent Schrodinger Equation and...
  10. D

    A Expectation values and trace over the environment

    I've worked through a Stern Gerlach experiment for the Sx and Sz directions using the density matrix formalism to account for the environment. This shows a result which I think is correct but relies on decoherence to give the "actual" value. I'm not confident about the result though. Would...
  11. naima

    A Stern Gerlach and decoherence

    In this paper Caldeira gives a model for the Stern Gerlach device in the vacuum. the incoming particle is described by the tensor product of a space term and a spin term a |u> + b |d> the SG is in the vacuum (no air around). Under the effect of the spatial variation of the magnetic field, there...
  12. G

    Stern Gerlach confusion

    Since the particles aren’t rotating, but just traveling in a straight line, there should be no angular momentum whatsoever. Since the magnetic moment of magnetic dipoles can be theoretically represented as coming from a loop of electric current, or particle orbiting, thus magnetic moments are...
  13. Ahmad Kishki

    The Mathematical Structure of QM and the Stern Gerlach

    Many books in QM (eg: Sakurai) mention that the stern-gerlach experiment provides enough motivation for the mathematical structure of QM, Sakurai even mentions Gottfried's book. Point is, i didnt find Gottfried's book, so i am looking for other books that develop the math of quantum mechanics...
  14. M

    Stern Gerlach and Nuclear Spin?

    So, my current understanding of spin is that when particles with a certain spin state hit a stern gerlach device, their wavefunction is split into components, deflection associated with one of the pure spin states aligned with the device. For spin 1/2 particles, there are only supposed to be two...
  15. T

    Stern Gerlach Spin 3/2, Quantum Mechanics

    Homework Statement [/B] Just trying to find the spin 3/2 rotation matrix, I've found spin 1/2 and spin 1. This isn't a homework problem just studying some other spins. Homework Equations For spin 1/2: Rn(Φ) = cos(Φ/2)1ˆ − isin(Φ/2)σn For spin 1: Un(Φ) = e −iΦSn = 1ˆ − isin(Φ) · Sn − (1ˆ −...
  16. M

    Stern Gerlach term in the Pauli Equation

    Where does the Stern Gerlach term in the Pauli equation come from? Taken from http://en.wikipedia.org/wiki/Pauli_equation. Following wikipedia's steps the Stern Gerlach term pops out when you apply the Pauli vector identity. I don't understand this step. It seems as if there should be no Stern...
  17. D

    Represent Action of Stern Gerlach Operator as a Matrix

    Homework Statement Given the series of three Stern-Gerlach devices: Represent the action of the last two SG devices as matrices ##\hat{A}## and ##\hat{B}## in the ##|+z\rangle, |-z\rangle## basis. Homework Equations ##|+n\rangle = cos(\frac{\theta}{2})|+z\rangle +...
  18. C

    Stern Gerlach Experiment and Spin

    I'm trying to get my head around this spin idea, the idea that particles behave like tiny dipole magnets when passing through a magnet field, either spin up or spin down. Because unlike magnets they don't produce a spread on at the end, they are either top or bottom. So the problem I have...
  19. B

    Stern Gerlach and Position Measurements

    Homework Statement Given the following stern-gerlach setup, find the probabilities for particles to arrive in detectors D1 and D2. SGx = Stern Gerlach in x direction, SGx = Stern Gerlach in z direction (sorry for terrible ascii drawing) |ψ> = a|+> + b|->, |ψ> is normalized. ..../D1...
  20. PsychonautQQ

    Why Does the Stern-Gerlach Experiment Only Have a Gradient in the Z Direction?

    I'm confused.So a dipole needs a nonuniform field for the net force to not equal zero, cool. My question is how do they go from F = -∇(μ * B) = ((μ_z)(dB/dz))*(z unit vector) how come the gradient has no x or y parts?
  21. mesa

    In the Stern Gerlach experiment, electron beam acceleration question

    In the Stern Gerlach experiment it would seem that an electron beam moving at some velocity bisecting the upper magnet on a horizontal path would be radially accelerated perpendicular to the direction of motion. I am assuming from Lenz's Law this can be corrected by increasing the Bf...
  22. C

    Aharonov-Bohm Effect & Spin 1/2 Particles

    Can I get a spin 1/2 particle to deflect with the aharonov bohm effect. Where the B field is zero but A is not? Or will it just change the phase in the state-vector? can I get the spin up particles to go one way and the spin down particles to go another way.
  23. C

    Did the particle deflect due to the change in B field to an E field in my frame?

    Lets say I have a uniform line charge moving at a speed v. This will create the B field for our stern-gerlach experiment. Now I shoot neutrons or some other particle with spin that will be affected by the B field. Now let's say I am moving with this line charge at speed v. In my frame there is...
  24. B

    Stern Gerlach expectation value

    Homework Statement An electron starts in a spin state |\psi(t=0)\rangle = |z \uparrow \rangle and evolves in a magnetic field B_0(\hat{x} + \hat{z}). The Hamiltonian of the system is \hat{H} = \alpha \vec{B}\cdot\vec{S}. Evaluate \langle \psi (t_{1/2}) | S_x | \psi(t_{1/2}) \rangle...
  25. stevenb

    Question about torque in Stern Gerlach Experiment

    I'm reading about the Stern Gerlach experiment in Sakurai's well-known book "Modern Quantum Mechanics". I remember studying this years ago, and somehow back then this question didn't enter my mind. However, I can't seem to figure out the answer. I understand that a gradient in magnetic field...
  26. Z

    How to realize the stern gerlach experiment ?

    Hey, Ok so basically what i want to do is to realize the stern gerlach experiment, I know it's going to be a lot of work , but I'm highly motivated... oh and btw I'm only 16 so I don't know everything about physics and I'm not a native speaker, so sorry for possible errors concerning my...
  27. E

    How Is Frequency Calculated in the Stern-Gerlach Experiment?

    Homework Statement I have a Stern-Gerlach experiment with a beam of silver and a magnetic moment due to the spin of the single valence electron give by μ=e/me S. And |S|=ℏ/2. The magnetic field is 1T. The problem asks to compute the energy difference of the silver atoms in the two...
  28. B

    Stern Gerlach Experiment, bra(c)kets etc

    Hi all, This is my first post to the physics forum. I am completely new to quantum physics and have just gone through lecture notes on the Schrödinger equation, infinite square well, hydrogen atom and angular momentum etc. I am currently starting on the Stern-Gerlach experiment, bras and...
  29. L

    How to make a large stern gerlach magnet

    Hello Forum, Does anyone know of any references on the construction of a Stern-Gerlach magnet? Most of the references I have seen so far discuss magnets that provide a constant field gradient (in the z-axis) over a few millimetres. Since I have a circular beam of about 1 cm diameter, I need a...
  30. I

    QM - stern gerlach and spin

    Homework Statement A beam delivering protons is sent through a stern-gerlach splitter oriented to ask whether the spin is oriented parallel to the y axis. What fraction of protons have spin down with respect to the y axis? \chi=\stackrel{1}{\sqrt{17}} \stackrel{4}{i} the 4, i thing is the...
  31. I

    Question on Stern Gerlach experiment

    In the Stern Gerlach experiment, when does the electron's position get determined? Before/right after it leaves the inhomogeneous field? Or when it hits the detecting foil? This could be tested by replacing the foil with two slits at each of the expected regions of electron incidence. If...
  32. Amith2006

    How does the Stern Gerlach experiment split a beam of hydrogen atoms?

    Homework Statement If a beam of hydrogen atoms in ground state are passed through an inhomogeneous magnetic field, into how many paths will the beam be split? Assume that the beam is moving towards the plane of this page and the magnetic field is directed in the upward direction in the plane...
  33. S

    Ensuring Clean Quantum Measurements in the Stern-Gerlach Experiment

    How do they make sure the "measurement" process in conventional Stern-Gerlach experiments are clean quantum measurements? Spins dynamically precess in magnetic fields (uniform or non-uniform) and Stern-Gerlach (especially sequential SG setups) make precise predictions regarding the resultant...
  34. Z

    Probability in the Stern Gerlach

    1.Show that one gets a 50% : 50% probability for deflection up and down in a y-Stern Gerlach measurement when atoms that are preselected as +x atoms or -x atoms are used as a source. What kind of the equation is it? Do we just need to find the coefficients and square them? 2.A source produces...
  35. F

    What is the problem with the Stern Gerlach J=1 exercise?

    Hello! i have a trouble with an exercise of a course of structure of matter. Helium atoms in the excited state 23S1 come out from a box at v=2000 m/s and pass trough an Stern & Gerlach apparatus with dB/dz=25 T/m and length L=0.30m. Atoms spends 1 hour in the box and the average-time for...
  36. maverick280857

    Measurement and Stern Gerlach Experiments review articles?

    Hi everyone In my attempt to understand the details of Stern Gerlach experiments and measurment issues in quantum mechanics, I have come to believe that there is a lot to be learned from some of the basic thought experiments like interference and Stern Gerlach described in books...
  37. maverick280857

    Commuting Operators in Sequential Stern Gerlach Experiment

    Hi everyone How do I show that the expression \sum_{b'}|\langle c'|b'\rangle|^{2}|\langle b'|a'\rangle|^{2} = \sum_{b'}\langle c'|b'\rangle\langle b'|a'\rangle \langle a'|b'\rangle \langle b'|c'\rangle equals the expression |\langle c'|a'\rangle|^{2} = |\sum_{b'}\langle c'|b'\rangle...
  38. R

    Stern Gerlach Gradient Field Strength

    I am trying to recreate the Stern-Gerlach experiment and am having trouble trying to calculate the gradient magnetic field. I am using two magnets with one having a sharp edge and the other flat. I have calculated what the deflection will be of the electron will be in terms of the gradient...
  39. P

    Calculating the Stern Gerlach Angle in Magnetic Fields

    How can you calcualte the angle of the split of the electrons after passing it thorugh a non uniform magnetic field? I know how to calculate it by elementary means using the magnitude of S and Sz and doing trig. But is that angle always the same no matter what intensity magnetic field its...
  40. D

    Stern Gerlach Experiment, Simple Question

    Really simple question: In the Stern Gerlach experiment they construct an electron spin filter with magnets: http://www.upscale.utoronto.ca/GeneralInterest/Harrison/SternGerlach/SternGerlach.html I'm not sure what would happen if you used the first set of magnets to split a beam of...
  41. S

    Can you unscramble a scrambled egg?

    Here is a fascinating article about the story of the landmark SG Experiment. http://www.physicstoday.org/vol-56/iss-12/p53.html There are some interesting twists to the tale, but I won't spoil them for you. Some contemporary reactions to the results:-...
  42. M

    Stern Gerlach Experiment: Understanding the Unexpected Results

    In the Stern Gerlach experiment the Ag beam is split in two beams of half intensity of the original beam due to the equal distribution of spin up and spin down electrons. Considering that each of the split beams is composed of only one type of electrons (let's say spin up), if we pass this...
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