Non-volatile programmable components for the superconducting computer

传统的硅基电子产品的散热是效率低下和环境影响的主要来源。超导体本质上是无耗散的。建立基于超导体的新的数字计算方案在能源效率方面提供了巨大的潜在收益，可以应用于超级计算机和数据中心等大规模需求，以降低ICT生态系统的整体碳足迹。数字超导计算机也有重要的利基应用，例如在量子比特的控制和读出方面。超导计算机的基本构件是约瑟夫森结，它被提议用来替代cmos晶体管。通过基于约瑟夫森结的逻辑电路进行计算不仅比CMOS技术更节能，而且速度更快。最大的遗留问题是低温存储器的发展滞后。传统的磁性和CMOS型存储器不能很好地适应低温工作。为了实现这些计算机承诺的效率提高，需要一种新型的低温存储体系结构。我们这里的建议旨在将超导电路与磁存储元件(如自旋阀)相结合，其中信息被编码到设备的磁性状态中，但写入和读出是由电路的超导元件实现的，以实现最大的能效并与计算机的其余部分兼容。传统上被认为是相互竞争的现象，当人为地并列在超导体和铁磁体之间的界面上时，出现了大量新的物理学。可以通过两种方式利用这些邻近效应来创造新的、高能效的设备。第一种是利用这两种现象之间的自然竞争，在这种现象中，信息通过包含铁磁垒的约瑟夫森结的“零pi”基态相位差来存储。第二种利用了一种独特的协同效应，以(等自旋)三重态库珀对的形式存在。这种新的三重态库珀对不会被铁磁体的交换场打破，从而为新型自旋电子器件提供了一个无耗散的自旋极化电流来源。我们计划在我们的研究计划中充分利用这些新物理，以打开我们设备的潜在新颖性。在超导计算领域，英国有被美国大型研究项目(如IARPA C3项目)甩在后面的风险。该计划将利用我们现有的专业知识和与美国领先集团的合作来开发前景广阔的低温存储器应用。

The dissipation of heat in traditional silicon (CMOS) based electronics is a major source of inefficiency and environmental impact. Superconductors are, by nature, dissipationless. Building a new digital computational scheme based on superconductors offers huge potential gains in energy efficiency, which could be applied to large scale needs such as supercomputers and data centres to lower the overall carbon footprint of the ICT ecosystem. Digital superconducting computers also have important niche applications such as in the control and read-out of qubits. The fundamental building block of the superconducting computer is the Josephson junction, which is proposed as a replacement for the CMOS transistor. Computing via logic circuits based on Josephson junctions is not only more energy efficient, but also faster than CMOS technologies. The largest remaining problem is the lagging development of low-temperature memory. Traditional magnetic and CMOS memories are not well suited for low-temperature operation. To achieve the promised efficiency increases of these computers requires a new type of low-temperature memory architecture. Our proposal here aims to combine superconducting circuits with magnetic memory elements, such as spin-valves, where the information is encoded into the magnetic state of the device but writing and read-out is achieved by the superconducting elements of the circuit for maximum energy efficiency and compatibility with the rest of the computer. Traditionally considered competing phenomena, when artificially juxtaposed a wealth of new physics at the interface between superconductors and ferromagnets emerges. It is possible to use these proximity effects to create new, highly energy efficient devices in two ways. The first exploits the natural competition between the phenomena, where information is stored by a "zero - pi" ground-state phase difference across a Josephson junction containing a ferromagnetic barrier. The second exploits a unique synergy, found in the form of the (equal spin) triplet Cooper pair. This new triplet Cooper pair is not broken by the exchange field of a ferromagnet, providing a dissipationless source of spin polarized current for use in novel spintronic devices. We plan to fully exploit these new physics in our research programme to open the potential novelty of our devices. The UK risks being left behind in the field of superconducting computing by large US research efforts such as the IARPA C3 programme. This programme will take advantage of our existing expertise and collaboration with leading US groups to develop the promising application of cryogenic memory.