Improving student understanding of addition of angular momentum in   quantum mechanics
  We describe the difficulties advanced undergraduate and graduate students have with concepts related to addition of angular momentum in quantum mechanics. We also describe the development and implementation of a research-based learning tool, a Quantum Interactive Learning Tutorial (QuILT), to reduce these difficulties. The preliminary evaluation shows that the QuILT related to the basics of the addition of angular momentum is helpful in improving students' understanding of these concepts. 
Guangtian Zhu and Chandralekha Singh
physics.ed-ph