CAREER:Topologically Protected Quantum Devices

University Of Maryland, College Park, College Park MD

Investigators

Abstract

NONTECHNICAL SUMMARY The Division of Materials Research and the Physics Division contribute funds to this CAREER award to support research and education aimed at generating and exploiting quantum behavior at a macroscopic level. While quantum mechanics naturally operates at the microscopic regime, i.e. length scales much smaller than those we experience daily, stabilizing macroscopic quantum phenomena in large quantum systems can be exceedingly difficult due to the detrimental influence of the unavoidable interaction of the system with its surroundings. One possible approach to creating macroscopic quantum phenomena is based on recently discovered topological phases in condensed matter systems, which for fundamental reasons are effectively protected from the environment. The funded research is aimed at studying the rich variety of static and dynamical phenomena that arise from the interplay of these novel topological phases with conventional physics, such as electrostatic interactions, lattice vibrations, and material impurities. From recent experiments it is becoming clear that the physics of these systems cannot be understood without considering these conventional ingredients. More optimistically, apart from helping in understanding experiments, exploring the physics resulting from this interplay will likely lead to the discovery of new phenomena, which could influence the design of quantum computers. The education component includes disseminating knowledge on topological phases through an extended online course coupled to an open access forum on the subject that target graduate and undergraduate students; a concept version of the course has recently generated substantial interest from many countries. The PI will complement this kind of international outreach to a broad spectrum of budding scientists with outreach specific to local students aimed at a more basic level. In collaboration with colleagues at the University of Maryland, the PI will contribute in running a seminar series that aims to retain underrepresented minority students who transfer to the physics department at the University of Maryland from local community colleges. TECHNICAL SUMMARY The Division of Materials Research and the Physics Division contribute funds to this CAREER award to support theoretical and computational research and education with the goal to extend the ideas of topological phases of matter and design robust quantum mesoscopic devices through the following steps: (1) analyzing the effects of phonons, interactions, and disorder on Majorana phases, (2) understanding the interplay of phase dynamics and topology in ultracold atomic gases, (3) stabilizing topological phases against disorder using quantum dot arrays, (4) using superconductors to generate phases beyond Majorana modes, (5) evaluating the robustness of excited topological states to interactions. Majorana modes, which are predicted to occur in certain topological phases of matter, are the most accessible examples of topological excitations. In addition to aiding the ongoing search for Majorana modes in solid-state systems, the research will provide insight into active areas of research in mesoscopic systems, topological materials, and quantum computation. The PI will use a combination of established analytical approaches, such as Keldysh perturbation theory, and state-of-the-art numerical techniques, to predict new phenomena relevant to mesoscopic quantum devices. The insight gained will be used to design new variants of topological materials. The intrinsic similarities of topological systems, e.g. the similarity of the toric code to quantum error correcting codes, will result in the research having impact on the quantum information community as well. The education component includes disseminating knowledge on topological phases through an extended online course coupled to an open access forum on the subject that target graduate and undergraduate students; a concept version of the course has recently generated substantial interest from many countries. The PI will complement this kind of international outreach to a broad spectrum of budding scientists with outreach specific to local students aimed at a more basic level. In collaboration with colleagues at the University of Maryland, the PI will contribute in running a seminar series that aims to retain underrepresented minority students who transfer to the physics department at the University of Maryland from local community colleges.