Localizing and Manipulating Exotic Quasiparticles in Quantum Hall Antidots

Suny At Stony Brook, Stony Brook NY

Investigators

Abstract

Nontechnical Abstract: In solid-state structures, quantum information can be stored and processed based on properties of quantum states. This project studies sub-micrometer diameter holes in two-dimensional atomic crystals, called "antidots", where the quantum states can have useful properties very different from those of electrons, including fractional charge and statistics. Such states potentially allow robust quantum information applications, and can be used to form artificial molecules. This project combines theoretical and experimental efforts to create and manipulate quantum states in antidot structures, and it could lead to the development of novel qubits. The technical aspects of this research combine material science, nanotechnology, electronics, cryogenics, theoretical condensed matter physics, and quantum information, and will provide students involved in the project with a unique opportunity to obtain experience in all these fields, and form the next generation of a “quantum-smart” workforce. The project also plans to develop an online, freely accessible software kit, “The World of Anyons”, to bring to the public an intuitive understanding of all aspects of the physics at the heart of this project. Technical Abstract: Two-dimensional (2D) electron systems host exotic quantum Hall (QH) states, including fractional QH states supporting abelian and non-abelian anyons, and excitonic states in double-layer QH systems. Being able to localize and manipulate quasiparticle excitations of these quantum states facilitates the study of the strongly interacting systems, and potentially leads to novel quantum devices which operate based on their non-trivial topological properties. This project studies the localization and manipulation of quantum Hall quasiparticles on QH antidots realized in graphene and its double-layers. In this approach, topologically protected QH edge modes are structured into discrete confining loops that localize the QH quasiparticles which carry the characteristics of the underlying incompressible QH liquid. This project explores: 1) robust localization of abelian anyons and understanding the decoherence and other basic physics elements of the individual QH antidots; 2) localization of non-abelian anyons and excitonic quasiparticles on individual antidots; 3) coupling of the antidots into the multi-antidot structures, and demonstration of anyon exchange and braiding in DC transport through a triple-antidot structure. The QH antidot approach to quantum gates is based on the adiabatic transfer of the individual topological excitations, which is the basis for the quasiparticle exchange statistics. This study advances the understanding of correlated electron systems and exchange/braiding properties of localized quasiparticles, and should provide direct insight into the stability of quantum coherence in topological braiding. 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.