Collaborative Research: Worm Algorithm and Diagrammatic Monte Carlo for Strongly Correlated Condensed Matter Systems

Cuny College Of Staten Island, Staten Island NY

Investigators

Abstract

NONTECHNICAL SUMMARY This award supports theoretical and computational studies of materials and systems in which their constituents (electrons, atoms, and ions) interact strongly with each other and, as a result, exhibit novel quantum behavior. The main research focus is on advancing fundamental understanding of unusual properties and phenomena which may lead to the development of future technologies. The PIs will employ advanced analytical methods and computational algorithms that they have developed to achieve accurate description of several key condensed matter systems at low temperature when collective quantum behavior of atoms and electrons results in the superconducting and superfluid states. Superconductivity and superfluidity are phenomena characterized by zero resistance and zero viscosity to the electron and fluid flows, respectively. These are related states of matter distinguished by the charge of the particles participating in the flow: in superconductors the flow is associated with charged electron pairs, while in superfluids it is due to the flow of neutral atoms such as, for example, Helium-4. In this project, various mechanisms responsible for superconductivity in prototypical systems and superfluidity in Helium-4 will be investigated. This project also supports training graduate students in advanced numerical techniques, quantum statistics, topical problems of condensed-matter and atomic physics, and high-performance computing. This project also helps to advance the Precision Many Body Physics Initiative which is aimed to facilitate international collaboration in cutting edge research directed toward understanding collective properties of matter, including quantum matter. Activities planned within this context include international workshops, Focused Sessions at American Physical Society March Meetings, and topical mini workshops. TECHNICAL SUMMARY This award supports theoretical and computational research with an aim to achieve a fundamental understanding of electronic and transport properties of a variety of condensed matter systems through the use of two state-of-the-art approaches to correlated quantum many-body systems: Worm Algorithm (WA) and Diagrammatic Monte Carlo (DiagMC); both introduced by the research team. The main goals of the project are: (i) WA-based studies of a new class of pseudo-one-dimensional superfluid systems called "transverse quantum fluids"; (ii) DiagMC studies of Cooper instability in the prototypical model of correlated electrons, uniform electron gas (with and without coupling to the phonon subsystem); and (iii) DiagMC studies of novel polaron and bipolaron states. This project also supports training graduate students in advanced numerical techniques, quantum statistics, topical problems of condensed-matter and atomic physics, and high-performance computing. This project also helps to advance the Precision Many Body Physics Initiative which is aimed to facilitate international collaboration in cutting edge research directed toward understanding collective properties of matter, including quantum matter. Activities planned within this context include international workshops, Focused Sessions at American Physical Society March Meetings, and topical mini workshops. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.