Fibre-based memory module for photonic quantum computing

我们正在开发光子量子计算机，它将使用被称为光子的单个光粒子，以比传统超级计算机更强大的方式执行计算任务。然而，光子量子计算机中的操作从根本上是不可靠的，因此需要存储元件来存储量子逻辑门的成功结果，直到所有操作都正确运行。在材料系统中存储光的一种方法是，利用明亮激光束介导的能级跃迁，将光子的量子态映射到原子云的集体激发中。几百纳秒后，通过再次打开激光器，光子就能被找回来。虽然存储时间似乎很短，但足以缓冲足够的门，以构建大规模的光子量子处理器。不幸的是，对于这种应用来说，具有最佳能级的原子是铷——一种难以处理的高活性元素——现有的量子存储器受到必须包含铷的蒸汽电池特性的限制。在这个项目中，我们将设计、建造和测试先进的蒸汽电池，这种电池在特殊光纤的空心核心中含有铷原子云。这不仅可以确保反应性铷不受环境的影响，而且还可以确保光在整个中空纤维的长度上与原子相互作用。结合我们的紧凑型光纤存储模块与其他光学元件集成的便利性，我们开发的产品将使更多数量的存储器能够以比以前更高的效率同时运行。这将为量子计算的科学和技术发展以及光子量子计算机在药物发现、工业过程优化或电池和太阳能电池新材料建模等社会挑战中的应用开辟新的市场。

We are developing photonic quantum computers that will use individual particles of light known as photons to carry out computational tasks in more powerful ways than conventional supercomputers. However, operations in photonic quantum computers are fundamentally unreliable, hence memory elements are required to store successful outcomes of quantum logic gates until all have functioned correctly.One way of storing light in a material system is by mapping the quantum state of a photon into a collective excitation of a cloud of atoms using an energy level transition mediated by a bright laser beam. The photon can then be retrieved a few hundreds of nanoseconds later by switching the laser on again. Although the storage time seems short, it is sufficient to buffer enough gates to build large-scale photonic quantum processors. Unfortunately, the atoms with the best energy levels for this application are rubidium -- a highly reactive element that is difficult to handle -- and existing quantum memories are limited by the characteristics of the vapour cells in which the rubidium must be contained.In this project, we will design, build, and test advanced vapour cells that contain clouds of rubidium atoms in the hollow cores of special optical fibres. This will ensure not only that the reactive rubidium remains protected from the environment but also that light can interact with atoms over the whole length of the hollow fibre. Combined with the ease with which our compact fibre memory modules will integrate with other optical components, the products that we develop will enable a much larger number of memories be operated simultaneously at much higher efficiencies than was previously possible. This will open up new markets both within the scientific and technological development of quantum computation and beyond in the applications of photonic quantum computers to societal challenges including drug discovery, industrial process optimisation, or modelling new materials for batteries and solar cells.