*66%*:**Student difficulties with quantum states while translating state vectors in Dirac notation to wave functions in position and momentum representations***49%*:**Improving studentsâ€™ understanding of quantum measurement. I. Investigation of difficulties***46%*:**Investigating Student Difficulties with Dirac Notation***46%*:**Student difficulties with determining expectation values in quantum mechanics***44%*:**Resources Students Use to Understand Quantum Mechanical Operators***42%*:**Student Difficulties in Understanding Probability in Quantum Mechanics***41%*:**Students' Difficulties with Quantum Measurement***39%*:**Student difficulties in learning quantum mechanics***38%*:**Investigating Student Difficulties with Time dependence of Expectation Values in Quantum Mechanics***38%*:**Investigation of Student Difficulties with Graphical Representations in Physics***37%*:**Student Difficulties with Quantum Mechanics Formalism***35%*:**Student Difficulties with Graphical Representations of Negative Values of Velocity***35%*:**Improving studentsâ€™ understanding of quantum measurement. II. Development of research-based learning tools***35%*:**Improving student understanding of addition of angular momentum in quantum mechanics***34%*:**Studentsâ€™ Difficulties in Transfer of Problem Solving Across Representations***34%*:**Addressing Student Models of Energy Loss in Quantum Tunneling***34%*:**Student difficulties in translating between mathematical and graphical representations in introductory physics***33%*:**Student Difficulties with Energy in Quantum Mechanics***33%*:**Analogous Patterns of Student Reasoning Difficulties in Introductory Physics and Upper- Level Quantum Mechanics**