*72%*:**Improving Students' Understanding of Quantum Mechanics***63%*:**Assessing and improving student understanding of quantum mechanics***61%*:**Students' understanding of the addition of angular momentum***61%*:**Improving students’ understanding of quantum measurement. II. Development of research-based learning tools***58%*:**Improving Students' Understanding of Quantum Mechanics***56%*:**Improving Students’ Understanding of Quantum Measurement***54%*:**The Influence of Student Understanding of Classical Physics When Learning Quantum Mechanics***54%*:**Improving students' understanding of quantum mechanics via the Stern–Gerlach experiment***54%*:**Investigating student understanding of basic quantum mechanics in the context of time-dependent perturbation theory***53%*:**Improving students’ understanding of quantum measurement. I. Investigation of difficulties***52%*:**Improving students' understanding of quantum mechanics by using peer instruction tools***51%*:**Student Difficulties in Understanding Probability in Quantum Mechanics***50%*:**Exploring Student Understanding of Energy through the Quantum Mechanics Conceptual Survey***46%*:**Student understanding of the angular momentum of classical particles***46%*:**Improving Students' Understanding of Lock-In Amplifiers***45%*:**Surveying Students’ Understanding of Quantum Mechanics***45%*:**Surveying students' understanding of quantum mechanics in one spatial dimension***44%*:**Testing the development of student conceptual and visualization understanding in quantum mechanics through the undergraduate career***44%*:**Student understanding of quantum mechanics**