Development of a cryofree ultra low temperature environment for quantum enhanced sensors

这项拟议的可行性研究汇集了牛津仪器的工业合作伙伴和兰开斯特大学的学术合作伙伴，以解决将一种用户友好、紧凑、便携的机器推向市场的问题，以满足当前和未来量子技术的商业应用，这些量子技术需要低噪音、低温、隔离环境才能发挥作用。在室温和与被观测系统强烈交互的环境中，量子力学的影响通常被噪声掩盖。极端隔离和低温通常被用来消除这些缺陷，因此，稀释式冰箱提供的极端寒冷和高真空是观察量子增强行为的理想环境。牛津仪器公司在提供提供这种环境的商业机器方面有着长期的声誉，兰开斯特大学的团队在利用低温来操纵、开发和测量量子行为方面非常熟练。在这次联合努力中，我们将开发一种新产品，帮助其他用户获得与周围环境隔离的超低温环境。传统的稀释制冷在第一个冷却阶段需要大量的液氦杜瓦尔。新型不含冷冻剂的干式稀释冰箱不需要液氦。OI是这项新技术的先驱，是市场领先者。我们现在将采取下一步行动，降低拥有规模和成本，并提高自动化程度。这将增加大学实验室和研究机构传统市场上的用户对这项技术的接受。这也将使工业制造商更容易将其作为组件包括在未来的设备和仪器中，这些设备和仪器利用需要超低温环境的量子增强行为。这里的例子是用于安全通信的固态量子计算机量子比特和信息处理设备的原型，这些设备基于超导量子干涉设备的特性，这些设备只能在稀释冰箱温度下工作。紧凑、自动化和廉价的冰箱将是这一市场的明显优势。此外，作为这类新技术的一个例子，我们将证明这种新产品将为通过量子力学增强性能的新型传感器技术提供理想的环境。在这里，我们将研究如何在磁场传感方面超越当前的灵敏度和分辨率限制。这已经在一系列现场应用中有用，从遥感新的石油/天然气储量到大脑和身体的医学成像。目前，最先进的测量磁场对超导结的影响，超导结由金属Nb制成，只冷却到绝对零度以上4度的液氦温度。通过使用新的无低温技术，我们将能够在两个方面提高灵敏度。第一种是通过简单地降低温度，从而减少热噪声。第二种更令人兴奋的方式是，有些材料只有在这些较低的温度下才能发挥作用，我们将能够研究用这些材料以新方式制造的新设备。例如，我们将能够用超导铝取代Nb，并使用纳米制造技术来制造半导体/超导/普通金属混合器件。我们还将能够研究含有石墨烯的设备，在这种设备中，较低的温度使电子能够在二维石墨烯中移动更远的距离，然后被噪声散射。我们合作的预期结果将是一个新的无低温系统的原型设计，该系统将使用量子增强传感器来改进对小磁场的检测。

This proposed feasibility study brings together industrial partners from Oxford Instruments and academic partners fromLancaster University to tackle the problem of bringing to market a user-friendly, compact, portable machine for current andfuture commercial applications in quantum technologies that need low-noise, low-temperature, isolated environments inorder to function.The effects of quantum mechanics are usually masked by noise at room temperatures and in environments that interactstrongly with the systems under observation. Extreme isolation and low temperatures are often used to remove thesenuisances, and the extreme cold and high vacuum provided by dilution refrigerators is therefore an ideal environment forobserving quantum-enhanced behaviour. Oxford Instruments have a longstanding reputation for their expertise in providingcommercial machines that deliver such environments, and the Lancaster University team is highly skilled in exploiting theselow temperatures to manipulate, exploit and measure quantum behaviour.In this joint endeavour we will develop a new product that will help other users gain access to the ultra-low temperatureenvironment isolated from its surroundings. Traditional dilution refrigeration has required bulky dewars of liquid helium forthe first cooling stage. New "dry" cryogen-free dilution fridges do not need liquid helium. OI has pioneered this newtechnology and is market leader. We will now take the next step of reducing the size and cost of ownership, and increasingautomation. This will increase the uptake of this technology by users in the traditional markets of university laboratories andresearch institutes. It will also make it easier for industrial manufacturers to include it as a component in future equipmentand instrumentation that exploit those quantum-enhanced behaviours which require the ultra-low temperature environment.Examples here are the prototype solid-state quantum computer qubits and information processing devices for securecommunications which are based on the properties of superconducting quantum interference devices that only work atdilution refrigerator temperatures. Compact, automatic and less expensive fridges will be an obvious benefit in this market.Further, and as an example of this type of new technology, we will demonstrate that this new product will provide the idealenvironment for new types of sensor technology whose performance is enhanced by quantum mechanics. Here we willinvestigate how to go beyond current sensitivity and resolution limits in the sensing of magnetic fields. This is already usefulin a range of in-the-field applications from remote sensing of new oil/gas reserves to medical imaging of the brain and body.At the moment the state-of-the-art measures the effect of magnetic fields on superconducting junctions that are made fromniobium metal and cooled only to liquid helium temperatures of 4 degrees above absolute zero. By using new cryo-freetechnology we will be able to improve sensitivity in two ways. The first is by simply being colder, so that thermal noise isreduced. The second, more exciting way, is that there are materials which only become functional at these lowertemperatures, and we will be able to investigate new devices made in new ways from these materials. For instance we willbe able to replace niobium with superconducting aluminium, and use nanofabrication techniques to make hybridsemiconductor/superconductor/normal metal devices. We will also be able to investigate devices which contain graphene,where the lower temperatures enable electrons to travel much greater distances within the two-dimensional graphenesheet before being scattered from their path by noise.The anticipated outcome of our collaboration will be a prototype-ready design for a new cryo-free system that will usequantum-enhanced sensors to improve the detection of small magnetic fields.