Learning the tensor network model of a quantum state using a few single-qubit measurements

The constantly increasing dimensionality of artificial quantum systems demands for highly efficient methods for their characterization and benchmarking. Conventional quantum tomography fails for larger systems due to the exponential growth of the required number of measurements. The conceptual solution for this dimensionality curse relies on a simple idea - a complete description of a quantum state is excessive and can be discarded in favor of experimentally accessible information about the system. The probably approximately correct (PAC) learning theory has been recently successfully applied to a problem of building accurate predictors for the measurement outcomes using a dataset which scales only linearly with the number of qubits. Here we present a constructive and numerically efficient protocol which learns a tensor network model of an unknown quantum system. We discuss the limitations and the scalability of the proposed method.Comment: 10 pages, 11 figure

Paleodietary patterns of the Cherepakha 13 site population (Early Iron Age) in Primorye (Maritime) province, Russian Far East, based on stable isotope analysis

New paleodietary data were obtained after the discovery and excavation in 2015–2017 of the Cherepakha 13 site in the southern part of Primorye (Maritime) Province in far eastern Russia. The site is located near the coast of Ussuri Bay (Sea of Japan) and belongs to the Yankovsky cultural complex of the Early Iron Age 14C-dated to ca. 3000 BP (ca. 1200 cal BC). The stable isotope composition of the bone collagen for 11 humans and 30 animals was determined. For humans, the following values (with ±1 sigma) were yielded: δ13C =–10.2 ± 0.8‰; and δ15N = +12.4 ± 0.3‰. The majority of terrestrial animals show the usual isotopic signals: δ13C =–19.4 ÷ –23.3‰; and δ15N = + 4.6 ÷+6.6‰ (for wolves, up to +10.1‰); dogs, however, have an isotopic composition similar to humans: δ13C = –11.7 ± 1.2‰; and δ15N = +12.4 ± 0.4‰. Marine mammals have common values for pinnipeds: δ13C =–13.7 ÷ –14.6‰; and δ15N = +17.4 ÷ +18.0‰. The main food resources for the population of Cherepakha 13 site were (1) marine mollusks, fish, and mammals; and (2) terrestrial mammals; and possibly C4 plants (domesticated millets)

Electrochemical study of semiconductor properties for bismuth silicate-based photocatalysts obtained via hydro-/solvothermal approach

Three bismuth silicate-based photocatalysts (composites of Bi2SiO5 and Bi12SiO20) prepared via the hydro-/solvothermal approach were studied using electrochemical methods. The characteristic parameters of semiconductors, such as flat band potential, donor density, and mobility of their charge carriers, were obtained and compared with the materials’ photocatalytic activity. An attempt was made to study the effect of solution components on the semiconductor/liquid interface (SLI). In particular, the Mott–Schottky characterization was made in a common model electrolyte (Na2SO4) and with the addition of glycerol as a model organic compound for photocatalysis. Thus, a medium close to those in photocatalytic experiments was simulated, at least within the limits allowed by electrochemical measurements. Zeta-potential measurements and electrochemical impedance spectroscopy were used to reveal the processes taking place at the SLI. It was found that the medium in which measurements were carried out dramatically impacted the results. The flat band potential values (Efb) obtained via the Mott–Schottky technique were shown to differ significantly depending on the solution used in the experiment, which is explained by different processes taking place at the SLI. A strong influence of specific adsorption of commonly used sulfate ions and neutral molecules on the measured values of Efb was shown

Possible Origin of Antimatter Regions in the Baryon Dominated Universe

We discuss the evolution of U(1) symmetric scalar field at the inflation epoch with a pseudo Nambu-Goldstone tilt revealing after the end of exponential expansion of the Universe. The U(1) symmetry is supposed to be associated with baryon charge. It is shown that quantum fluctuations lead in natural way to baryon dominated Universe with antibaryon excess regions. The range of parameters is calculated at which the fraction of Universe occupied by antimatter and the size of antimatter regions satisfy the observational constraints, survive to the modern time and lead to effects, accessible to experimental search for antimatter.Comment: 10 pages, 1 figur

Crowdsourcing Fungal Biodiversity : Revision of Inaturalist Observations in Northwestern Siberia

The paper presents the first analysis of crowdsourcing data of all observations of fungi (including lichens) and myxomycetes in Northwestern Siberia uploaded to iNaturalist.org to date (24.02.2022). The Introduction presents an analysis of fungal diversity crowdsourcing globally, in Russia, and in the region of interest. Materials and methods describe the protocol of uploading data to iNaturalist.org, the structure of the crowdsourcing community. initiative to revise the accumulated data. procedures of data analysis, and compilation of a dataset of revised crowdsourced data. The Results present the analysis of accumulated data by several parameters: temporal, geographical and taxonomical scope, observation and identification efforts, identifiability of various taxa, species novelty and Red Data Book categories and the protection status of registered observations. The Discussion provides data on usability of crowdsourcing data for biodiversity research and conservation of fungi, including pros and contras. The Electronic Supplements to the paper include an annotated checklist of observations of protected species with information on Red Data Book categories and the protection status, and an annotated checklist of regional records of new taxa. The paper is supplemented with a dataset of about 15 000 revised and annotated records available through Global Biodiversity Information Facility (GBIF). The tradition of crowdsourcing is rooted in mycological societies around the world, including Russia. In Northwestern Siberia, a regional mycological club was established in 2018, encouraging its members to contribute observations of fungi on iNaturalist.org. A total of about 15 000 observations of fungi and myxomycetes were uploaded so far, by about 200 observers, from three administrative regions (Yamalo-Nenetsky Autonomous Okrug, Khanty-Mansi Autonomous Okrug, and Tyumen Region). The geographical coverage of crowdsourcing observations remains low. However. the observation activity has increased in the last four years. The goal of this study consisted of a collaborative effort of professional mycologists invited to help with the identification of these observations and analysis of the accumulated data. As a result, all observations were reviewed by at least one expert. About half of all the observations have been identified reliably to the species level and received Research Grade status. Of those, 90 species (195 records) represented records of taxa new to their respective regions: 876 records of 53 species of protected species provide important data for conservation programmes. The other half of the observations consists of records still under-identified for various reasons: poor quality photographs, complex taxa (impossible to identify without microscopic or molecular study). or lack of experts in a particular taxonomic group. The Discussion section summarises the pros and cons of the use of crowdsourcing for the study and conservation of regional fungal diversity, and summarises the dispute on this subject among mycologists. Further research initiatives involving crowdsourcing data must focus on an increase in the quality of observations and strive to introduce the habit of collecting voucher specimens among the community of amateurs. The timely feedback from experts is also important to provide quality and the increase of personal involvement.Peer reviewe

Paleodietary patterns of the Cherepakha 13 site population (Early Iron Age) in Primorye (Maritime) province, Russian Far East, based on stable isotope analysis

New paleodietary data were obtained after the discovery and excavation in 2015–2017 of the Cherepakha 13 site in the southern part of Primorye (Maritime) Province in far eastern Russia. The site is located near the coast of Ussuri Bay (Sea of Japan) and belongs to the Yankovsky cultural complex of the Early Iron Age 14C-dated to ca. 3000 BP (ca. 1200 cal BC). The stable isotope composition of the bone collagen for 11 humans and 30 animals was determined. For humans, the following values (with ±1 sigma) were yielded: δ13C =–10.2 ± 0.8‰; and δ15N = +12.4 ± 0.3‰. The majority of terrestrial animals show the usual isotopic signals: δ13C =–19.4 ÷ –23.3‰; and δ15N = + 4.6 ÷+6.6‰ (for wolves, up to +10.1‰); dogs, however, have an isotopic composition similar to humans: δ13C = –11.7 ± 1.2‰; and δ15N = +12.4 ± 0.4‰. Marine mammals have common values for pinnipeds: δ13C =–13.7 ÷ –14.6‰; and δ15N = +17.4 ÷ +18.0‰. The main food resources for the population of Cherepakha 13 site were (1) marine mollusks, fish, and mammals; and (2) terrestrial mammals; and possibly C4 plants (domesticated millets)

New records and range expansion of Calosoma sycophanta (Linnaeus, 1758) (Coleoptera, Carabidae) in Western Siberia, Russia

In this study, we report about 25 records of Calosoma sycophanta (Linnaeus, 1758) from Western Siberia collected in the last 21 years (1997–2017). We extend the known distribution of this species in the Tyumen, Kurgan, Omsk and Novosibirsk regions of Russia. New records extend the known distribution of C. sycophanta for 300 km to the north, and for 600 km to the east, in the Western Siberia. These new distributional data may contribute to a re-evaluation of its conservation status

Laser-assisted preparation of highly-efficient photocatalytic nanomaterial based on bismuth silicate

Having a wide range of applications, bismuth silicate-based materials (BSO) attract attention of numerous researchers. Typically, they are synthesized either from active chemicals or through high-energy impact on their precursors. The present work is the first report on BSO-based nanomaterials prepared via laser processing in liquid phase in which the following two-step scheme was realized: (1) Individual colloids of Bi- and Si-based nanoparticles were obtained via ablating their metallic targets in distilled water and then mixed; (2) Posttreatment of the mixed colloid was performed with the same laser beam as in stage (1). The products obtained after drying of non-treated and post-treated mixed colloids (denoted as samples BSO and BSO_hν, respectively) were carefully characterized using a set of microscopic, spectroscopic and electrochemical analyses, after which their photocatalytic performance in presence of model organic dye (rhodamine B) and phenol was tested. The additional laser treatment was found to lead to active interaction between Bi- and Si-containing species and stimulated formation of phases with Bi-O-Si bonds. The post-irradiated sample BSO_hν showed improved stability and catalytic performance, thus opening avenues for wider use of laser processing in liquids as a method allowing for preparation of nanostructures with complex chemical composition

Chronology of Prehistoric Cultural Complexes of Sakhalin Island (Russian Far East)

From the 18th International Radiocarbon Conference held in Wellington, New Zealand, September 1-5, 2003.A chronological framework for the prehistoric cultural complexes of Sakhalin Island is presented based on 160 radiocarbon dates from 74 sites. The earliest 14C-dated site, Ogonki 5, corresponds to the Upper Paleolithic, about 19,500-17,800 BP. According to the 14C data, since about 8800 BP, there is a continuous sequence of Neolithic, Early Iron Age, and Medieval complexes. The Neolithic existed during approximately 8800-2800 BP. Transitional Neolithic-Early Iron Age complexes are dated to about 2800-2300 BP. The Early Iron Age may be dated to about 2500-1300 BP. The Middle Ages period is dated to approximately 1300-300 BP (VII-XVII centuries AD).The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

Raman Study of Block Copolymers of Methyl Ethylene Phosphate with Caprolactone and L-lactide

We present an in-depth analysis of Raman spectra of novel block copolymers of methyl ethylene phosphate (MeOEP) with caprolactone (CL) and L-lactide (LA), recorded with the excitation wavelengths of 532 and 785 nm. The experimental peak positions, relative intensities and profiles of the poly(methyl ethylene phosphate) (PMeOEP), polycaprolactone (PCL) and poly(L-lactide) (PLA) bands in the spectra of the copolymers and in the spectra of the PMeOEP, PCL and PLA homopolymers turn out to be very similar. This clearly indicates the similarity between the conformational and phase compositions of PMeOEP, PCL and PLA parts in molecules of the copolymers and in the PMeOEP, PCL and PLA homopolymers. Experimental ratios of the peak intensities of PMeOEP bands at 737 and 2963 cm−1 and the PCL bands at 1109, 1724 and 2918 cm−1 can be used for the estimation of the PCL—b—PMeOEP copolymers chemical composition. Even though only one sample of the PMeOEP—b—PLA copolymers was experimentally studied in this work, we assume that the ratios of the peak intensities of PLA bands at 402, 874 and 1768 cm−1 and the PMeOEP band at 737 cm−1 can be used to characterize the copolymer chemical composition