The Entangled spin ½ particle pairs versus an elementary hidden variable theory simulation allows students to assess whether a simple hidden variable theory would agree with measurement outcomes predicted by quantum theory. The simulation shows a source of particle pairs in the middle of two Stern-Gerlach apparatuses (SGAs), one of which can be rotated with respect to the other. The observers measure outcomes of + or – (depicted as flashes on the screens) irrespective of orientation depending on whether the deflection is positive or negative along the measurement axis. When the main controls are set to “Quantum theory”, the particles pairs are entangled and always give opposite results when both SGAs have the same orientation. When the main controls are set to “Hidden variable theory”, the particles in the pair have pre-determined opposite spin vectors that are randomly oriented in space. An accompanying activity for this simulation is available at http://quantumphysics.iop.org and at www.st-andrews.ac.uk/physics/quvis. The simulation can be downloaded from the QuVis website www.st-andrews.ac.uk/physics/quvis.
This simulation is part of the UK Institute of Physics New Quantum Curriculum, see http://quantumphysics.iop.org. Simulations and accompanying activities can be accessed from the IOP site and from www.st-andrews.ac.uk/physics/quvis. Sharing of these resources is encouraged, with all usage under the Creative Commons CC BY-NC-ND licence. Instructors can email email@example.com for activity solutions and to request to modify materials.