My research interests include quantum coherence in nanoscale electrical circuits (solid-state qubits), dynamics of individual electrons in one-dimensional conductors, and ultrafast quantum-limited charge measurements. Recent advances in nanolithography and cryogenic electronics have made it possible to sense individual electrons as they move through nanometer-sized conductors. My research exploits this ability to detect the quantum superposition of macroscopically distinct states of electrical circuits and to detect the flow of single electrons through molecular wires. My current work addresses the following questions: What are the sources of decoherence in solid-state qubits? How efficiently and how quickly do electrons screen each other in nanoscale circuits? Can a sensor of charge reach quantum-limited sensitivity?