Nonlinear quantum processes in superconducting resonators terminated by neon-focused-ion-beam-fabricated superconducting nanowires

利用氖聚焦离子束制备的毫开尔文铌纳米SQUID嵌入式可调谐振器

Millikelvin Nb nanoSQUID-embedded tuneable resonator fabricated with a neon focused-ion-beam

本文提出一种利用氖聚焦离子束制备的铌纳米SQUID嵌入式谐振器，在16 mK下实现频率可调，并表征其磁通灵敏度及噪声来源，展示了其在混合超导-自旋应用中的潜力。

Tunable Nb superconducting resonators based upon a Ne-FIB-fabricated constriction nanoSQUID

Hybrid superconducting--spin systems offer the potential to combine highly coherent atomic quantum systems with the scalability of superconducting circuits. To fully exploit this potential requires a high quality-factor microwave resonator, tunable in frequency and able to operate at magnetic fields optimal for the spin system. Such magnetic fields typically rule out conventional Al-based Josephson junction devices that have previously been used for tunable high-$Q$ microwave resonators. The larger critical field of niobium (Nb) allows microwave resonators with large field resilience to be fab…

Ultra-thin Epitaxial MgB2 on SiC: Substrate Surface Polarity Dependent Properties

High quality, ultrathin, superconducting films are required for advanced devices such as hot-electron bolometers, superconducting nanowire single photon detectors, and quantum applications. Using Hybrid Physical-Chemical Vapor Deposition (HPCVD), we show that MgB2 films as thin as 4 nm can be fabricated on the carbon terminated 6H-SiC (0001) surface with a superconducting transition temperature above 33K and a rms roughness of 0.7 nm. Remarkably, the film quality is a function of the SiC surface termination, with the C-terminated surface preferred to the Si-terminated surface. To understand th…

Controllable tunnelling of single flux-quanta mediated by quantum phase-slip in disordered superconducting loops

Quantum phase-slip (QPS) is the exact dual to the well-known Josephson effect. Although there are numerous proposals for applications of QPS devices, experimental work to develop these remains in the relatively early stages. Significant barriers to exploiting QPS nanowires for useful technologies still exist, such as establishing robust nanowire fabrication methods that allow coupling to low-loss circuits, and demonstrating control over the QPS process with an experimenter-controlled external bias. Here we report experiments which show that both of these barriers have been overcome. We present…

具有单片三维（3D）纳米桥结的铌量子干涉微波电路

Niobium Quantum Interference Microwave Circuits with Monolithic Three-Dimensional (3D) Nanobridge Junctions

本文提出在铌微波谐振器中单片集成三维纳米桥超导量子干涉器件，通过氖离子束铣削实现，获得与铝器件相当的非线性性能且工作参数范围更大，为混合量子系统应用奠定基础。

使用直流电流可调超导微波谐振腔提取单片集成三维纳米收缩结构的电流-相位关系

Extracting the current-phase-relation of a monolithic three-dimensional nano-constriction using a DC-current-tunable superconducting microwave cavity

本文提出一种单片集成3D纳米收缩结构的直流可调铌微波谐振腔，通过表征偏置电流对谐振特性的影响重构其电流-相位关系，并分析Kerr非线性，为微波电路中非线性元件的全面表征提供新方法。