*****NON-TECHNICAL ABSTRACT**** This individual investigator award supports a project with the primary goal of increasing our understanding of the fundamental quantum physics of many-electron systems. Quantum electrons have wave-like properties, and can interfere similar to the light waves. Unlike light, electrons are electrically charged particles, and the electrical current carried by electrons is used to carry information in all modern electronic equipment, such as computers and communications gear. This project will explore the quantum interference of electrons in novel ways, which may be useful for a quantum computer. Quantum computers store and process information in quantum bits (qubits), not just the 0 and 1 of the classical computers. This has been shown theoretically to lead to a vastly improved performance in many important applications. There are several difficulties, however. One is that the electron waves are affected by thermal and electromagnetic random fluctuations, losing "coherence", so that the interference pattern is damaged and the quantum information carried by the electrons is lost. What's left is the ordinary "classical" information (a tiny fraction of quantum) that is used in today's electronics. The project will explore ways to make the quantum nature of the electron waves more robust, specifically exploring use of novel electron devices functioning in a very high magnetic field and at low temperatures (so-called "Quantum Hall effect"). Students are rigorously trained in advanced techniques to enter positions in industry, government and education.
This award supports research on fundamental quantum properties of condensed matter probed via well-characterized system of two-dimensional electrons. The lower-dimensional electrons manifest many-body quantum mechanics, such as the fractional quantum Hall effect, the one-dimensional chiral edge states, and the fractionally-charged Laughlin quasiparticle tunneling phenomena in interferometer devices and quantum antidots. The quantum-coherent properties of the collective ground states of two-dimensional electrons in lithographically-defined devices, their excitations and chiral edge state dynamics will be studied experimentally at ultra low temperatures and very high magnetic fields. The techniques developed in the fabrication and experimental study of the quantum-coherent quantum Hall devices are aimed at exploring novel territory and advancing the state-of-the-art measurements. The quantum interferometer and antidot physics may form the basis of novel fault-tolerant quantum computing. This research project involves collaborations with materials scientists and electrical engineers in sample preparation and with theorists in analysis of experimental results. Students, including members of underrepresented groups, are rigorously trained in cryogenic, high vacuum, electronics, and sample fabrication techniques to enter positions in industry, government and education.
