This award supports theoretical research and education to address a fundamental question in quantum condensed matter physics: How do condensed matter systems behave when they are driven far from equilibrium? The PI aims to investigate how standard methods that have proven very successful in revealing the quantum ground states of many body systems may be extended and applied to nonequilibrium systems. These methods include mean-field theory, fluctuations about mean field and the renormalization group. The PI will focus on two classes of systems: The first class is quantum impurity models that are coupled to external reservoirs. The second class is spatially extended systems that are close to an ordering-disordering quantum phase transition. The PI will address the following issues: a). The precise mechanism underlying nonequilibrium induced decoherence, and the extent to which decoherence may be regarded as an effective temperature; b). Conditions under which a nonequilibrium probe can produce instabilities that could drive the many body system to a novel steady state or a time dependent dynamical state with no thermal analog; c). The effect of conservation laws on nonequilibrium induced phase transitions. The outcome of the research will be relevant to experiments in quantum dots, single molecule devices, spintronics and driven cold atom systems. This award supports guidance and training to students. By providing them with an opportunity to interact with theoretical and experimental groups in the physics department, as well as with members of the Courant Institute of Mathematical Sciences at New York University, students will get a broad exposure and a well rounded education.
NON-TECHNICAL SUMMARY:
This award supports theoretical research and education to study condensed matter systems that are out of balance with their surroundings and for which quantum mechanics dominates. These quantum nonequilibrium systems include atomic structures on the nanoscale, such as quantum dots and molecules. For these systems, the successful theoretical methods developed to understand and describe systems that are in balance with their surroundings do not work and the PI seeks to develop extensions of these equilibrium methods to nonequilibrium systems, particularly those in a steady state, such as constant electric current going through a molecule or nanostructure. This general problem also arises in atomic and optical physics, biophysics and quantum information theory and the PI's approach should apply to a broad range of nonequilibrium systems. This research contributes to the broad fundamental understanding of the world around us. The focus of the research on nanostructures and systems of impurities is particularly relevant to contributing to the theoretical foundations to enable the design of possible future electronic devices and information technology. This award also supports guidance and training of students. By providing them with an opportunity to interact with theoretical and experimental groups in the physics department, as well as with members of the Courant Institute of Mathematical Sciences at New York University, students will get a broad exposure and a well rounded education.
