Towards quantum control of topological phases in mesoscopic superconductors

利用量子叠加和纠缠运行的技术将彻底改变世界存储，处理和通信信息的方式。量子计算机有望通过计算在经典计算机之间分配计算任务的最佳方式来提高云计算的效率。在材料科学中，量子计算机也可以更有效地模拟化学反应的演变，因此它们可能有助于合成化学的发展，在合成化学中，理解大分子的行为将导致更智能的节能材料。量子模拟器还将阐明量子效应在与光合作用等能量收集相关的生物过程中的作用，并为具有异国情调的节能能力（如高温超导性）的材料设计提供信息。量子计算机分解多项式时间的能力也可能对互联网安全产生巨大影响，目前互联网安全依赖于分解大量数字几乎不可能。量子计算机的核心是被称为量子比特或“量子比特”的构建块，它在物理上包括两个可以被操纵成任何量子叠加的状态。我们在建造量子计算机时面临的挑战之一是防止环境通过棘手和无意的相互作用杀死这些脆弱的叠加。大多数量子比特都是基于熟悉的粒子，例如量子点中的电子，原子阱中的离子或波导中的光子，目前还不清楚优化其性能的最终限制是什么。解决这个问题的另一种优雅的方法是找到一个本质上不受环境影响的量子位。一个这样的量子比特使用了被称为任意子的奇异粒子，它可以对量子比特的状态进行非局部编码。与环境的弱相互作用永远不会使其状态崩溃，使其作为量子存储器更加强大。这项研究的目的是通过开发用于观察与超导体接触的二维气体中电子集体运动产生的任意子的设备和技术，为量子控制这种量子比特铺平道路。非常值得注意的是，在像石墨烯这样简单而著名的材料中，已经存在具有非常相似性质的颗粒，尽管尚未被检测到。我的策略是通过监测单个电子如何在纳米器件中与它们相互作用来暴露这些粒子的存在。从长远来看，我预计具有更严格拓扑保护的材料将会出现，我的愿望是使用这里开发的技术来存储，操纵和读出无退相干的量子信息。

Technologies which operate using quantum superposition and entanglement are set to revolutionise how the world stores, processes, and communicates information. A quantum computer is expected to improve the efficiency of cloud computing by calculating the optimal way to distribute computational tasks amongst classical computers. In materials science, the evolution of chemical reactions is also more efficiently simulated by a quantum computer so they are thus likely to aid developments in synthetic chemistry, where understanding the behaviour of large molecules will lead to smarter power-saving materials. Quantum simulators will also elucidate the role of quantum effects in biological processes related to energy harvesting such as photosynthesis, and inform the design of materials with exotic power-saving capabilities such as a high-temperature superconductivity. The ability for quantum computers to factor in polynomial time could also have an enormous impact on internet security, which currently relies on the near impossibility of factoring large numbers. At the heart of quantum computers are building blocks known as quantum bits, or "qubits", which physically comprise two states that can be manipulated into any quantum superposition. One of the challenges we face with building a quantum computer is preventing the environment from killing these fragile superpositions through intractable and unintentional interactions. Most qubits are based on familiar particles, such as electrons in a quantum dot, ions in an atom trap, or photons in a waveguide, and it is unclear what the ultimate limit will be in the race to optimise their performance. An alternative and elegant approach to this problem is to find a qubit that is intrinsically protected from interacting with the environment. One such qubit employs exotic particles, known as anyons, that can encode the state of a qubit non-locally. Weak interactions with the environment can never collapse its state, making it more robust as a quantum memory. The aim of this research is to pave the way towards quantum control of such qubits by developing devices and techniques for observing anyons that emerge from the collective motion of electrons in a two-dimensional gas in contact with a superconductor. Quite remarkably, particles with very similar properties are already available, though not yet detected, in a material as simple and famous as graphene. My strategy is to expose the presence of these particles by monitoring how single electrons interact with them in nanodevices. In the longer term I anticipate materials with stricter topological protection to be come available, and my aspiration is to use the techniques developed here to store, manipulate, and read out decoherence-free quantum information.