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 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.

Deep multilevel wet etching of fused silica glass microstructures in BOE solution.

Fused silica glass is a material of choice for micromechanical, microfluidic, and optical devices due to its chemical resistance, optical, electrical, and mechanical performance. Wet etching is the key method for fabricating of such microdevices. Protective mask integrity is a big challenge due extremely aggressive properties of etching solution. Here, we propose multilevel microstructures fabrication route based on fused silica deep etching through a stepped mask. First, we provide an analysis of a fused silica dissolution mechanism in buffered oxide etching (BOE) solution and calculate the main fluoride fractions like [Formula: see text], [Formula: see text], [Formula: see text] as a function of pH and NH4F:HF ratio. Then, we experimentally investigate the influence of BOE composition (1:1-14:1) on the mask resistance, etch rate and profile isotropy during deep etching through a metal/photoresist mask. Finally, we demonstrate a high-quality multilevel over-200 µm etching process with the rate up to 3 µm/min, which could be of a great interest for advanced microdevices with flexure suspensions, inertial masses, microchannels, and through-wafer holes.

Photon Transport in a Bose-Hubbard Chain of Superconducting Artificial Atoms.

We demonstrate nonequilibrium steady-state photon transport through a chain of five coupled artificial atoms simulating the driven-dissipative Bose-Hubbard model. Using transmission spectroscopy, we show that the system retains many-particle coherence despite being coupled strongly to two open spaces. We find that cross-Kerr interaction between system states allows high-contrast spectroscopic visualization of the emergent energy bands. For vanishing disorder, we observe the transition of the system from the linear to nonlinear regime of photon blockade in excellent agreement with the input-output theory. Finally, we show how controllable disorder introduced to the system suppresses nonlocal photon transmission. We argue that proposed architecture may be applied to analog simulation of many-body Floquet dynamics with even larger arrays of artificial atoms paving an alternative way towards quantum supremacy.

[Control of the radiation protection of medical personnel during transcutaneous nephro-ureterolithotomy]. / Kontrol' radiatsionnoi zashchity meditsinskogo personala pri chreskozhnoi nefroureterolitotomii.

The authors describe methods to ensure radiation safety of medical personnel, used in transcutaneous nephro-ureterolithotomy. The results of measurements of an exposure dose rate and calculations of an equivalent dose are presented. They do not exceed standard maximum permissible doses.

[Glycoproteins in rat blood serum and tissues and thiamine saturation of the body]. / Glikoproteiny syvorotki krovi i tkanei krys pri razlichnom nasyshchenii organizma tiaminom

In blood serum and tissues of rats with alimentary and antimetabolic thiamin deficiencies content of glycoproteins was determined. The alimentary B1-avitaminosis caused a decrease in content of ceruloplasmin, hexosamines and sialic acids in blood serum and also of hexosamines in liver tissue and aorta. In dificiency of thiamin, caused by a single administration of hydroxythiamin, content of hexosamines and sialic acids were decreased in liver, pancreas and heart; in blood serum content of ceruloplasmin was decreased but that of glycoproteins was increased. Thiamin increased content of glycoproteins and sialic acids in blood serum and the content of sialic acids in liver tissue, but it decreased content of hexosamines in liver and pancreas. Content of the metabolites studied in animals, maintained on avitaminous diet, was normalized by means of repeated administration of thiamin during four weeks.