This award supports theoretical research and education in the area of strongly interacting Fermi systems. This project is closely tied to current experiments in two different classes of systems, ultracold atomic gases and complex materials, and will lead to fundamental insights into quantum many-body physics.
In the area strongly interacting atomic gases, the PI will focus on: (i) the study of superfluid, ferromagnetic, and Fermi liquid phases, (ii) spectroscopic probes of pairing gaps and pseudogaps, and (iii) kinetic coefficients like shear and bulk viscosities and their anomalous behavior in the unitary regime. Many of the issues that will be addressed have interesting counterparts in solid state materials. These include questions like the possible existence of a ferromagnetic ground state in a single band repulsive model, or that of a normal state pairing pseudogap in strongly attractive Fermi gases, and questions about transport coefficients in regimes where quasiparticles are not well-defined. The PI will also explore the similarities between spectroscopic probes like momentum-resolved radio-frequency spectroscopy of cold atoms and angle-resolved photoemission in complex materials.
A part of the project will deal with questions that are at the present time of direct interest only in complex materials. The PI will focus on the effect of disorder in strongly-correlated states which arise from doping Mott insulators. On the one hand, disorder gives rise to nanoscale inhomogeneity which plays a major role in determining observable properties, and on the other hand, it also acts as a local perturbation that gives new insights into the strongly correlated electronic state. A striking example is how disorder effects seem to be strongly suppressed in strongly correlated superconductors.
The research will involve training graduate students in important problems at the frontiers of research. Parts of the research will lead to cross-fertilization between the fields of atomic, molecular and optical physics, condensed matter physics, and high energy physics. The PI will continue to disseminate his results through talks and lectures at international conferences and summer schools, and to communicate the excitement of scientific research to undergraduates and high school students through popular lectures.
NON-TECHNICAL SUMMARY
This award supports theoretical research and education to study the emergent properties of systems of interacting particles which lies at the heart of condensed matter physics. Some of the most interesting properties arise when the constituents are strongly interacting. The PI aims to gain theoretical insight into two classes of problems involving strongly interacting atoms in ultracold atomic gases and in complex solid state materials. Ultracold atomic gases are gases of atoms that are cooled using lasers or magnetic fields to temperatures very close to the absolute zero of temperature. This theoretical research is strongly motivated by recent experiments. The PI's goal is to obtain new insights and to make predictions that are testable through experiment. Parts of the research have an overlap with areas of physics as diverse as nuclear and high energy physics. The work on correlated materials aims to address the important questions like why the high temperature superconductors are unusually robust against impurities and imperfections in the materials, a matter of both fundamental and practical importance.
The research will involve training graduate students in important problems at the frontiers of research. Parts of the research will lead to cross-fertilization between the fields of atomic, molecular and optical physics, condensed matter physics, and high energy physics. The PI will continue to disseminate his results through talks and lectures at international conferences and summer schools, and to communicate the excitement of scientific research to undergraduates and high school students through popular lectures.
The goal of this project was to gain theoretical insights into two classes of problems that focus on the emergent properties of strongly interacting quantum systems. The first set of problems involved ultracold atomic gases and the second involved quantum materials. Several new, and unexpected, results were obtained, which led to the theoretical understanding of existing experimental data and also gave rise to predictions for new experiments. This constituted the intellectual merit of the research. Some of the highlights of the results obtained in this project include: (i) the derivation of new exact results for the viscosity spectral functions of strongly interacting Fermi gases; (ii) the development of a new paradigm for understanding superconductor-insulator transitions; (iii) recent progress on new insights into magnetism at oxide interfaces. The research on cold atoms has a broad impact on diverse areas of physics outside the discipline of condensed matter physics. The work on quantum materials has potential technological impact. The project involved the training and mentoring of doctoral graduate students in cutting-edge areas of science. The outcomes of the project were disseminated through publications in high-impact peer-reviewed journals, invited talks at major international conferences and pedagogical lectures at international schools. The excitement and importance of science was communicated to a wider audience through public talks and also through lecture-demonstrations aimed at middle and high school students.
