High-Q trenched aluminum coplanar resonators with an ultrasonic edge microcutting for superconducting quantum devices

Dielectric losses are one of the key factors limiting the coherence of superconducting qubits. The impact of materials and fabrication steps on dielectric losses can be evaluated using coplanar waveguide (CPW) microwave resonators. Here, we report on superconducting CPW microwave resonators with internal quality factors systematically exceeding 5x106 at high powers and 2x106 (with the best value of 4.4x106) at low power. Such performance is demonstrated for 100-nm-thick aluminum resonators with 7-10.5 um center trace on high-resistivity silicon substrates commonly used in quantum Josephson junction circuits. We investigate internal quality factors of the resonators with both dry and wet aluminum etching, as well as deep and isotropic reactive ion etching of silicon substrate. Josephson junction compatible CPW resonators fabrication process with both airbridges and silicon substrate etching is proposed. Finally, we demonstrate the effect of airbridges positions and extra process steps on the overall dielectric losses. The best quality fa ctors are obtained for the wet etched aluminum resonators and isotropically removed substrate with the proposed ultrasonic metal edge microcutting.Comment: 6 pages, 2 figure

Broadband SNAIL parametric amplifier with microstrip impedance transformer

Josephson parametric amplifiers have emerged as a promising platform for quantum information processing and squeezed quantum states generation. Travelling wave and impedance-matched parametric amplifiers provide broad bandwidth for high-fidelity single-shot readout of multiple qubit superconducting circuits. Here, we present a quantum-limited 3-wave-mixing parametric amplifier based on superconducting nonlinear asymmetric inductive elements (SNAILs), whose useful bandwidth is enhanced with an on-chip two-section impedance-matching circuit based on microstrip transmission lines. The amplifier dynamic range is increased using an array of sixty-seven SNAILs with 268 Josephson junctions, forming a nonlinear quarter-wave resonator. Operating in a current-pumped mode, we experimentally demonstrate an average gain of $17 dB$ across $300 MHz$ bandwidth, along with an average saturation power of $- 100 dBm$, which can go as high as $- 97 dBm$ with quantum-limited noise performance. Moreover, the amplifier can be fabricated using a simple technology with just a one e-beam lithography step. Its central frequency is tuned over a several hundred megahertz, which in turn broadens the effective operational bandwidth to around $1.5 GHz$.Comment: 7 pages, 3 figure

Applied Risk Management Experience Organization of the Machine-Building Complex

В настоящей статье проведён обзор опубликованных исследований о проблемах, связанных с анализом и управлением рисками. На практике идентифицированы, оценены и проанализированы риски организации машиностроительного комплекса с последующим построением карты рисков и предложением стратегий по их предотвращению.This article provides a review of published studies on issues related to analysis and risk management. In practice identified, assessed, and analyzed risks of the organization of machine-building complex, followed by the construction of risk maps and offer strategies to prevent them

High-Q trenched aluminum coplanar resonators with an ultrasonic edge microcutting for superconducting quantum devices

Abstract Dielectric losses are one of the key factors limiting the coherence of superconducting qubits. The impact of materials and fabrication steps on dielectric losses can be evaluated using coplanar waveguide (CPW) microwave resonators. Here, we report on superconducting CPW microwave resonators with internal quality factors systematically exceeding 5 × 106 at high powers and 2 × 106 (with the best value of 4.4 × 106) at low power. Such performance is demonstrated for 100-nm-thick aluminum resonators with 7–10.5 um center trace on high-resistivity silicon substrates commonly used in Josephson-junction based quantum circuit. We investigate internal quality factors of the resonators with both dry and wet aluminum etching, as well as deep and isotropic reactive ion etching of silicon substrate. Josephson junction compatible CPW resonators fabrication process with both airbridges and silicon substrate etching is proposed. Finally, we demonstrate the effect of airbridges’ positions and extra process steps on the overall dielectric losses. The best quality factors are obtained for the wet etched aluminum resonators and isotropically removed substrate with the proposed ultrasonic metal edge microcutting

Cross coupling of a solid-state qubit to an input signal due to multiplexed dispersive readout

The integration, scale up and multiplexing arrays of superconducting qubits in quantum circuits are one of the main challenges of superconducting quantum technology. Here, we experimentally investigate the solid-state qubit multiplexing readout scheme, containing coplanar quarter-wavelength resonators coupled with planar Xmon-type qubit, connected to a common coplanar transmission line. We find that the qubit energy spectrum modifies in the presence of an additional exciting signal at the neighbour resonators fundamental frequency. We attribute the origin of this effect to electromagnetic field propagating through the common ground plane, which changes the qubits characteristics. Our finding may be useful for the development of scalable superconducting quantum integrated circuits with arrays of multiplexed/coupled qubits for applications in superconducting quantum processing and computing