Activity: Sequential Stern-Gerlach Experiments

Quantum Fundamentals 2022 (3 years)
  • Media
    • activity_media/SGIntro_S_n.png
    • activity_media/SGIntro_table1.png
  1. Set-Up a Sequential Measurement

    1. Add an analyzer to the experiment by:

      1. Break the links between the analyzer and the counters by clicking on the boxes with up and down arrow labels on the analyzer.
      2. Click and drag a new connection from the analyzer to empty space to create a new element. A new analyzer is one of the options.

    2. Measure \(S_z\) twice in succession.

      What is the probability that a particle leaving the first analyzer with \(S_z=\frac{+\hbar}{2}\) will be measured by the second analyzer to have \(S_z=\frac{-\hbar}{2}\)?

    3. Try all four possible combinations of input/outputs for the second analyzer.

      What have you learned from these experiments?


  2. Try All Combinations of Sequential Measurements

    In the table, enter the probability of a particle exiting the 2nd analyzer with the spin indicated in row if the particle enters the 2nd analyzer with the spin indicated in each column.


  3. You can rotate the Stern-Gerlach analyzers to any direction you want (using spherical coordinates).

    Choose an arbitrary direction (not along one of the coordinate axes) for the 1st analyzer and measure the spin along the coordinate directions for the 2nd analyzer.


Learning Outcomes