CAREER: Novel Quantum Ordered States from Strong or Long-Range Interaction in Multicomponent Systems

University Of Massachusetts Amherst, Amherst MA

Investigators

Abstract

TECHNICAL SUMMARY This CAREER award supports theoretical research and education on new states of matter that may arise in condensed matter. The research focuses broadly on two areas. Novel quantum order states of matter. A quantum ordered state restores its broken symmetries via a proliferation of topological defects. In conventional quantum fluids and gases only the simplest topological defects are important. The PI will investigate different possibilities which might arise in multicomponent quantum fluids and gases with strong or long-range intercomponent interaction. In such systems there can be phase transitions associated with proliferation of complex bound states of topological defects which do not produce a complete restoration of symmetry. It can lead to formation of new types of the aggregate "super" states of matter with partially broken symmetries such as metallic and superconducting superfluids which may arise at ultrahigh pressures in hydrogen isotopes and hydrogen-rich alloys. The PI plans to develop a theory and to predict experimental manifestations and possible probes of these projected new states of matter. The PI will investigate the properties of paired superfluids and super-counter-fluids in mixtures of Bose-Einstein condensates of cold atoms in optical lattices Magnetic response of multicomponent superconductors beyond the Meissner effect. The Meissner effect is the quintessential property of a single-component superconductor. The PI will investigate whether in some multicomponent systems gauge field fluctuations render the effective description mappable to Faddeev-Skyrme-like effective models at certain length scales. The magnetic response of these systems might differ fundamentally from the Meissner effect. The PI will investigate whether this results in topological defects in which energy is a non-monotonic function of the defect size. Existence of such defects in multicomponent systems may result in entirely novel physics. The PI will also investigate the properties of "type-1.5" superconductivity and the conditions under which it appears. This is a superconducting state with non-monotonic vortex interaction potential which can arise in multicomponent, for example two-band, superconductors. The magnetic response of this state is different from that of traditional type-I and type-II superconductors. The educational activities are aimed at bridging classroom education with independent research training through an original implementation of the Problem Based Learning concept used in medical schools and other areas for teaching Natural Sciences. The educational and research part will be integrated also by creating a broad course which will cover in a unified way concepts from condensed matter physics, high energy physics, and cosmology. NON-TECHNICAL SUMMARY This CAREER award supports theoretical research and education seeking to predict the existence of new states of matter that may occur in materials under a wide range of conditions. The research focuses on states of matter where a macroscopically large number of electrons or atoms can act in a lock-step fashion according to the laws of quantum mechanics. This leads to phenomena that are a reflection of the counterintuitive laws of the quantum world, the world of the smallest particles like electrons and atoms, but on the macroscopic human scale. Superconductivity, a state of electrons that can conduct electricity without dissipation, is an example which occurs in some materials at low temperature. The PI will study new kinds of quantum fluids that may arise in the electrons in complex materials, the element hydrogen under very high pressures which lies at the frontiers of experiments, and atoms that are cooled close to the absolute zero of temperature and trapped by laser beams. The educational activities are aimed at bridging classroom education with independent research training through an original implementation of the Problem Based Learning concept used in medical schools and other areas for teaching Natural Sciences. The educational and research part will be integrated also by creating a broad course which will cover in a unified way concepts from condensed matter physics, high energy physics, and cosmology.