EAGER: BRAIDING: Transport studies of the anyon braiding

非技术摘要：近年来，量子计算一直是人们感兴趣的一个主要研究课题。量子计算的实现是基于量子比特(Qubit)的创建和操作。虽然这种改变范式的想法已经知道30多年了，但量子计算机的实现仍处于非常早期的阶段。一个主要的挑战是将量子退相干降到最低，这是由各种因素引起的，例如量子系统与环境之间的相互作用。对于这一挑战，一个潜在的解决方案是利用量子比特的拓扑量子计算，量子比特的相干性受到保护。本文提出的工作旨在通过研究电荷输运特征，从实验上实现拓扑量子计算的基础。拟议的工作结合了理论和实验的努力。这一结果可能会为未来如何控制个体拓扑激发的研究提供直接指导，可能会导致拓扑量子计算的新量子比特的发展取得突破。这项拟议的研究为参与该项目的学生带来了材料科学(纳米材料)、纳米技术、电子学、低温学、理论凝聚态物理和量子信息科学的结合。此外，还将开展推广活动，包括石溪大学西蒙斯暑期研究项目和物理与天文学系周五晚上的物理世界讲座。技术摘要：基于任意子准粒子编织的拓扑量子计算概念潜在地为量子计算中的退相干挑战提供了一种解决方案。这项研究的目的是探索利用一种装置来操纵拓扑态的可能性，在这种装置中，任意子激发的编织是作为传输过程的一部分自动实现的，而不需要依赖于时间的控制。该装置由三点结构组成，其输运特性通过点间隧道效应表现出任意子激发的编织统计特性。在两种材料系统中对这种方案进行了研究。1)具有支持分数量子霍尔态和任意子带电准粒子的解毒剂的二维电子气；2)支持Majorana模的拓扑绝缘体/S波超导异质结。在这两个系统中，源漏电流的测量提供了关于准粒子任意子统计的信息。这项工作绕过了个体拓扑激发的随时间变化控制的困难，直接研究了拓扑编织的基础：准粒子交换统计及其输运特征。了解任意子激发的量子干涉和拓扑编织对任意子统计的影响，为拓扑量子计算奠定了科学基础。这里提出的技术方法将直接回答拓扑编织如何影响电荷传输特性，以及包括温度和无序在内的各种参数如何影响量子相干。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Nontechnical Abstract: Quantum computing has been a major research topic of interest in recent years. The realization of quantum computing is based on creation and manipulation of quantum bits (qubits). While this paradigm-changing idea has been known for over 30 years, the realization of quantum computers is still at the very early stage. A major challenge is to minimize quantum decoherence, originated from various factors such as the interaction between a quantum system and the environment. Towards this challenge, a potential solution is topological quantum computing which utilizes qubits whose coherence is protected. The proposed work here aims to experimentally realize the very foundation of topological quantum computing, by studying the charge transport signatures. The proposed work combines theoretical and experimental efforts. The outcome may provide direct guidance for future research on how to control individual topological excitations, potentially leading to breakthroughs in the development of novel qubits for topological quantum computing. The proposed research brings a combination of material science (nanomaterials), nanotechnology, electronics, cryogenics, theoretical condensed matter physics and quantum information science to students involved in the project. In addition, outreach activities, including Stony Brook University Simons summer research program and Department of Physics and Astronomy's World of Physics Friday evening lectures will be carried out to the general public. Technical Abstract: The concept of topological quantum computing, based on anyonic quasiparticle braiding, potentially offers a solution to the decoherence challenge in quantum computing. The objective of the proposed research is to investigate the possibility to manipulate the topological states with a set-up in which the braiding of anyonic excitations is achieved automatically as a part of the transport process without the need for the time-dependent control. The set-up consists of a triple-dot structure, whose transport characteristics manifest the braiding statistics of the anyonic excitation through inter-dot tunneling. Such scheme is studied in two types of material systems. 1) 2DEG with 'antidots' which support fractional quantum Hall states and anyonic charged quasiparticles; 2) topological insulator/s-wave superconductor heterojunctions which support Majorana modes. In both systems, measurements of the source-drain current provide information on the quasiparticle anyon statistics. The proposed work bypasses the difficulty in time-dependent controlling over the individual topological excitations and directly investigate the basis for the topological braiding: the quasiparticle exchange statistics and its transport signature. Understanding the quantum interference of the anyonic excitations and the impact of topological braiding on the anyonic statistics lays the scientific foundation of topological quantum computing. The technical approach proposed here will provide direct answers to how topological braiding impacts on the charge transport characteristics, and how various parameters including temperature and disorder affect quantum coherence.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.