This award supports theoretical research and education on quantum computing by manipulating quantum states of matter composed of many electrons. Quantum computers promise an exponential speedup for certain computational tasks which are not feasible with modern classical computers. The potential benefits would have impact from quantum chemistry to designing new medicines and materials to cryptographic applications. One of the main obstacles to building a working quantum computer is decoherence: by interacting with its surroundings, a quantum bit, or qubit, tends to become more and more classical. So, after a short time all potential advantages stemming from computation based on the laws of Quantum Mechanics are gone. The idea of Topological Quantum Computing (TQC) circumvents this problem by encoding quantum information in a combined state of a large number of interacting particles, as opposed to relying on quantum states of an individual particle which are more vulnerable to the usual sources of decoherence. Such robust many particle quantum states, called topologically ordered states, may exist in materials or materials may be engineered to support such states. But topological qubits and logical elements are still lacking. The goal of this project is to study topologically ordered and related phases of matter - a prerequisite for TQC. The PI aims to address three questions: (1) What are the most suitable physical systems where topological phases with the right properties may be realistically found? (2) How can candidate phases be manipulated to prepare quantum mechanical states and perform logical operations in a practical manner? (3) How can information be recovered from the candidate states, particularly since they are designed to be weakly influenced by the environment and so, not easily measured? These questions form the core of this project; answering them involves research across many modern themes of condensed matter physics at the interface with quantum computation and quantum information science. The PI will build on his previous work to develop introductory seminars on quantum computing and an outreach effort to California State campuses with an aim, in part, to broaden participation of underrepresented minorities.
This award supports theoretical research and education on the realization of quantum computing with topological phases of matter. The main goal of this project is to study topological phases of matter with the emphasis on their potential utility for Topological Quantum Computing. A part of this project aims at further investigating experimental signatures of non-Abelian anyons in quantum Hall systems at 5/2 filling, providing theoretical support for ongoing experiments and designing realistic quantum circuit elements based on these systems. A related activity will involve searching for similar physics in seemingly different types of systems such as chiral topological superconductors or itinerant electron systems interacting with local magnetic moments. A significant part of this project aims to understand how to engineer novel material systems with non-Abelian anyons by, for example, combining such 'building blocks' as Abelian fractional quantum Hall systems and conventional superconductors - an approach inspired by the conceptual designs of Majorana wires. The PI will build on his previous work to develop a conceptual framework for such engineering, further developing it as well as designing new measurement and manipulation techniques suitable for these systems. While much of the proposed activity deals with studying physical properties of the systems suitable for topological quantum computing, this research is aimed to advance the idea of topological quantum computing. Designing realistic quantum circuit elements based on these systems and developing new techniques for manipulating quantum information are integral parts of the planned research activity. The PI will build on his previous work to develop introductory seminars on quantum computing and an outreach effort to California State campuses with an aim, in part, to broaden participation of underrepresented minorities.
