Superconducting NbSi Quantum Phase-Slip Nanowire Devices for Electronics

我们将基于一种称为量子相移(QPS)的量子力学现象，开发超导器件，使其能够在高科技电子产品中应用。作为一个整体，该提案涉及在超导纳米线中发展这一迄今鲜有发展的量子力学表现形式。这些进展将是我们对物理学的基本理解，通过对最近提出的理论进行实验测试，以及通过开发将在未来纳米级应用中有用的电路元件而走向具体应用。未来潜在应用的一个具体领域是作为量子比特技术的元素，因此这项研究适合于使量子计算技术成为可能的更广泛的研究努力。相干QPS设备的开发将为开发一系列具有潜在技术重要性的新设备以及基础研究开辟道路。相干QPS器件可能在基础科学和计量学中都有应用，其影响可能与超导量子干涉器件(或称SQUID)一样显著，超导量子干涉器件是我们将开发的相干QPS器件之一的双重。这些设备还可能与量子计算应用相关，既可以作为量子比特本身，也可以作为未来使用先前开发的固态量子比特实现的有用电路元件。也有可能发展一种基于QPS的量子电流标准，这将对计量界产生重大影响。当超导序参数的量子涨落足够强，以至于序参数的相位滑移时，就会发生量子相移。每个设备的关键元素将是超导纳米线。如果这样的纳米线的横截面足够小，量子涨落可能会产生重大影响，可能会发生QPS事件。在这种情况下，电荷和超导相之间的基本量子力学海森堡不确定性关系可能会显著改变流经该设备的电流，甚至会与直觉相反，完全阻止电荷沿导线的传输，即使它是超导的。这是物理量子力学性质的结果。在这项研究中，我们将利用伦敦纳米技术中心最先进的纳米制造设施，开发基于量子相移的设备。我们将首次在实验中实现一系列相干QPS器件-包括偏置磁通和偏置电流的QPS晶体管和QPS盒-以期在未来的设备中应用，我们将在以前实验工作的基础上进行改进，以实现基于QPS的电流标准原型。

We will develop superconducting devices to enable applications in high-technology electronics, based on a quantum-mechanical phenomenon known as quantum phase-slip (QPS). The proposal as a whole is concerned with developing this so-far-little-developed manifestation of quantum mechanics within superconducting nanowires. The developments will be both in our fundamental understanding of the physics, through experimental tests of recently proposed theories, and in moving towards concrete applications by development of circuit elements which will be useful in future nanoscale applications. One specific area of potential for future application is as elements for qubit technologies and thus the research fits into the broader research effort of enabling technologies for quantum computing.The development of coherent QPS devices would open up avenues for developing a gamut of new devices of potential technological importance, as well as for fundamental research. Coherent QPS devices are likely to find applications in both fundamental science and metrology, and the impact could be as marked as the superconducting quantum interference device (or SQUID), which is dual to one of the coherent QPS devices we will develop. The devices are also likely to be of relevance to quantum computing applications, both as qubits in the own right and also as useful circuit elements in future realisations using previously developed solid-state qubits. There is also potential for a QPS-based quantum current standard to be developed and this would have substantial impact on the metrology community.A quantum phase-slip occurs when quantum fluctuations in the superconducting order parameter are sufficiently strong that the phase of the order parameter slips. The key element of each device will be a superconducting nanowire. If such a nanowire has a cross-section sufficiently small, quantum fluctuations may have significant effects and QPS events may occur. In that case, the fundamental quantum-mechanical Heisenberg uncertainty relation between the charge and superconducting phase may noticeably change the current flow through the device and even, counterintuitively, completely block charge transport along the wire, even though it is superconducting. This is a result of the quantum-mechanical nature of the physics.In this research we will develop devices based on the quantum phase-slip, using the state-of-the-art nanofabrication facilities in the London Centre for Nanotechnology. We will experimentally realise a range of coherent QPS devices - including the flux-biased and current-biased QPS transistors and the QPS box - for the first time, with a view to future applications in devices, and we will build on and refine previous experimental work with the aim of realising a prototype QPS-based current standard.