University of Oxford - Equipment Account

在过去半个世纪的人类历史中，随着计算机、高速通信网络和互联网的兴起，我们在处理和传播信息的能力方面经历了一场令人难以置信的革命。进展的速度仍然非常快，但随着处理设备的尺寸缩小到接近单个原子的规模，一个重大挑战即将出现。在如此微小的长度尺度上，控制电子设备运行的物理原理发生了根本性的变化，服从量子力学定律，计算机处理器也不再能像今天这样以传统方式运行。这个即将到来的地平线既是挑战也是机遇。从理论上讲，量子力学实际上可以用于以“经典”系统不可能实现的方式进行计算和通信，现在许多科学学科正在进行大量的研究工作，以实际方式实现这种量子通信和计算。在这项研究中，各种有前途的候选系统将被用于未来量子电子芯片上的量子比特（量子位），并以真正的量子相干方式进行研究。由超导电路制成的静态量子比特，以及半导体芯片上被困在孤岛上的电子，将与电子芯片上以光量子（光子）和振动运动量子（声子）的形式“飞行”的量子比特耦合在一起，这些量子比特被冷却到接近绝对零度的最低量子力学能态。这项研究将解决一些关键问题，如信息的脆弱量子性质在这样的系统中可以持续多久，如何使不同的系统相互作用和交换量子信息，以及如何将它们组合在一起，最终形成未来量子计算机的基本构建块，如量子逻辑门和量子存储器。该研究的一个特别重点是探索一个被称为腔QED的系统的潜力，在这个系统中，原子（或静态量子比特）和光（或飞行量子比特）之间的相互作用通过在形成腔的镜子之间捕获光来增强。这样的系统使得以比自由空间高得多的速率观察原子/量子比特和光之间的能量或信息交换成为可能。在这个特殊的项目中，这种情况是通过在电子芯片表面捕获微波频率光子或声子来实现的，在芯片上的腔内制造静态量子比特。这种用于腔QED和量子计算的架构被认为是非常有前途的，因为使用现有的传统处理器制造技术可以将其扩展到更大数量的量子位。

In the last half century of human history we have seen an incredible revolution in our ability to process and disseminate information, with the rise of computers, high speed communication networks, and the internet. The pace of progress is still extremely high, but a major challenge is on the horizon, as the size of processing devices shrinks to approach the scale of single atoms. At such tiny length scales, the physics governing the operation of electronic devices changes fundamentally to obey the laws of quantum mechanics, and computer processors could no longer operate in the conventional way that they do today. This approaching horizon is both a challenge and an opportunity. It has now long been known theoretically that quantum mechanics can in fact be used to carry out computing and communication in ways that are impossible with 'classical' systems, and a large research effort is now underway across many scientific disciplines to realize such quantum communication and computation in a practical way.In this fellowship, a variety of promising candidate systems for use as quantum bits (qubits) on future quantum electronic chips will be brought together and investigated in a truly quantum coherent manner. Static qubits made from superconducting electric circuits, and electrons trapped in islands on semiconductor chips will be coupled to 'flying' qubits in the form of quanta of light (photons) and quanta of vibrational motion (phonons) on electronic chips cooled to their lowest quantum mechanical energy state at close to absolute zero. The research will address key questions of how long the fragile quantum nature of information can last in such systems, how the different systems can be made to interact and exchange quantum information, and how they can be brought together to ultimately form the basic building blocks of future quantum computers, such as quantum logic gates and quantum memories.A particular focus of the research is to explore the potential of a system known as cavity QED in which the interaction between atoms (or static qubits) and light (or flying qubits) is enhanced by trapping the light between mirrors that form a cavity. Such a system makes it possible to observe the exchange of energy or information between the atoms/qubits and the light at a much higher rate than in free space. In this particular project, this scenario is realized with microwave frequency photons or phonons trapped on the surface of an electronic chip, with static qubits fabricated in place inside the on-chip cavities. This architecture for cavity QED, and for quantum computing, is thought to be highly promising since scaling it up to larger numbers of qubits may be achieved using conventional processor fabrication techniques that exist today.