A high threshold code for modular hardware with asymmetric noise

We consider an approach to fault tolerant quantum computing based on a simple error detecting code operating as the substrate for a conventional surface code. We develop a customised decoder to process the information about the likely location of errors, obtained from the error detect stage, with an advanced variant of the minimum weight perfect matching algorithm. A threshold gate-level error rate of 1.42% is found for the concatenated code given highly asymmetric noise. This is superior to the standard surface code and remains so as we introduce a significant component of depolarising noise; specifically, until the latter is 70% the strength of the former. Moreover, given the asymmetric noise case, the threshold rises to 6.24% if we additionally assume that local operations have 20 times higher fidelity than long range gates. Thus for systems that are both modular and prone to asymmetric noise our code structure can be very advantageous.Comment: 11 pages, 6 figure

Hydrogeochemical and isotopic study of the origins of groundwater salinization in the deep confined aquifer of northern Yangtze River

The deep confined water of coastal plain of northern Yangtze River suffers salinization. That results from overexploitation. This work aims to investigate the geochemical processes that lead to the salinization for this aquifer. Multiple environmental tracers of major ions, minor ions and isotopes (18O, 87Sr, 13C) were used to yield reasonable conclusions. The TDS of the aquifer ranges from 387 to 2600 mg/L. The aquifer is mainly composed of fresh water. Brackish water is distributed in the eastern and southern coastal areas, and is scattered in some inland areas. The water chemical type evolves from HCO3-Na to Cl-Na as TDS increases. Groundwater salinization is caused by mixing with saline water of marine origin. The aquifer is also affected by other hydrochemical processes. Silicate weathering and carbonate dissolution add Na+, K+, Ca2+, Mg2+ and HCO3- to groundwater. Sulfate reduction makes sulfate be deficient and HCO3- be enriched. Carbonate minerals equilibrium limits the increase in the concentrations of Ca2+, Mg2+ and HCO3-. Cation exchange reduces the concentration of Ca2++Mg2+ and increases the concentration of Na++K+. The aforementioned processes have a combined influence on the formation of fresh water with HCO3-Na type

Large-Scale Synthesis of Carbon Nanomaterials by Catalytic Chemical Vapor Deposition: A Review of the Effects of Synthesis Parameters and Magnetic Properties

The large-scale production of carbon nanomaterials by catalytic chemical vapor deposition is reviewed in context with their microwave absorbing ability. Factors that influence the growth as well as the magnetic properties of the carbon nanomaterials are discussed

The influence of MOF modification on oxygen evolution and reduction reaction of Fe-doped GdBaCo2O5+δ perovskite

Herein, Fe doping in the B-site of GdBaCo2O5+δ is adopted, that is, GdBaCo2-xFexO5+δ (X = 0.1, 0.2, 0.3, 0.4, 0.5), as efficient electrocatalysts in the alkaline conditions. It was found that Fe doping significantly improved the oxygen evolution reaction (OER) activity of GdBaCo2O5+δ, and the most active electrocatalyst GdBaCo1.6Fe0.4O5+δ showed a low overpotential of 298 mV at 10 mA cm−2. Subsequently, MOF ZIF-67 modification was carried out on the surface of GdBaCo1.6Fe0.4O5+δ, which greatly improved its oxygen reduction reaction (ORR) activity. The modified perovskite shows a high half-wave potential (0.850 V) and the enhanced electrocatalytic stability, which is superior to pristine perovskite and Pt/C

Room temperature ferromagnetism in ZnO prepared by microemulsion

Clear room temperature ferromagnetism has been observed in ZnO powders prepared by microemulsion. The O vacancy (VO) clusters mediated by the VO with one electron (F center) contributed to the ferromagnetism, while the isolated F centers contributed to the low temperature paramagnetism. Annealing in H2 incorporated interstitial H (Hi) in ZnO, and removed the isolated F centers, leading to the suppression of the paramagnetism. The ferromagnetism has been considered to originate from the VO clusters mediated by the Hi, leading to the enhancement of the coercivity. The ferromagnetism disappeared after annealing in air due to the reduction of Hi