Abstract
The idea of topological quantum computation is to build powerful and robust quantum computers with certain macroscopic quantum states of matter called topologically ordered states. These systems have degenerate ground states that can be used as robust “topological qubits” to store and process quantum information. In this paper, we propose a new experimental setup that can realize topological qubits in a simple bilayer fractional quantum Hall system with proper electric gate configurations. Our proposal is accessible with current experimental techniques, involves well-established topological states, and, moreover, can realize a large class of topological qubits, generalizing the Majorana zero modes studied in recent literature to more computationally powerful possibilities. We propose three tunneling and interferometry experiments to detect the existence and nonlocal topological properties of the topological qubits.
1 More- Received 6 August 2013
DOI:https://doi.org/10.1103/PhysRevX.4.041035
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Published by the American Physical Society
Popular Summary
The goal of quantum computation is to harness the laws of quantum mechanics in order to store and process information in fundamentally more powerful ways than current, classical computers can. However, an intrinsic difficulty to building a quantum computer is that quantum states are so fragile that the smallest amounts of environmental noise can unravel their intricate patterns of entanglement. Topological quantum computation overcomes this problem by utilizing certain macroscopic quantum states of matter called topologically ordered states. These systems have degenerate ground states that are intrinsically robust to environmental perturbations, providing an ideal platform for quantum computation. We propose a new experimental setup that can realize topological qubits, which can be used to process and store quantum information.
Our setup consists of two layers of a two-dimensional electron system, each forming the most stable and well-studied fractional quantum Hall state that has already been realized since the early 1980s. By using proper electric gate configurations—top and bottom gates, which prompt interlayer tunneling based on electron backscattering—we show that one can effectively change the topology of the space to which the electrons are confined, ultimately giving rise to a topological qubit. We propose three experimental tests of the topological qubit: an interlayer fractional quantized Hall conductance, measurement of certain localized topological zero modes via a technique analogous to scanning tunneling microscopy, and an interferometry measurement to detect the nonlocal nature of the topological qubit.
These tests are accessible with current experimental techniques, involve well-established topological states, and moreover, can realize a large class of topological qubits, generalizing the current proposals to more computationally powerful possibilities.