Demonstrating a Continuous Set of Two-Qubit Gates for Near-Term Quantum Algorithms.

Quantum algorithms offer a dramatic speedup for computational problems in material science and chemistry. However, any near-term realizations of these algorithms will need to be optimized to fit within the finite resources offered by existing noisy hardware. Here, taking advantage of the adjustable coupling of gmon qubits, we demonstrate a continuous two-qubit gate set that can provide a threefold reduction in circuit depth as compared to a standard decomposition. We implement two gate families: an imaginary swap-like (iSWAP-like) gate to attain an arbitrary swap angle, θ, and a controlled-phase gate that generates an arbitrary conditional phase, ϕ. Using one of each of these gates, we can perform an arbitrary two-qubit gate within the excitation-preserving subspace allowing for a complete implementation of the so-called Fermionic simulation (fSim) gate set. We benchmark the fidelity of the iSWAP-like and controlled-phase gate families as well as 525 other fSim gates spread evenly across the entire fSim(θ,ϕ) parameter space, achieving a purity-limited average two-qubit Pauli error of 3.8×10^{-3} per fSim gate.

Diabatic Gates for Frequency-Tunable Superconducting Qubits.

We demonstrate diabatic two-qubit gates with Pauli error rates down to 4.3(2)×10^{-3} in as fast as 18 ns using frequency-tunable superconducting qubits. This is achieved by synchronizing the entangling parameters with minima in the leakage channel. The synchronization shows a landscape in gate parameter space that agrees with model predictions and facilitates robust tune-up. We test both iswap-like and cphase gates with cross-entropy benchmarking. The presented approach can be extended to multibody operations as well.

Fluctuations of Energy-Relaxation Times in Superconducting Qubits.

Superconducting qubits are an attractive platform for quantum computing since they have demonstrated high-fidelity quantum gates and extensibility to modest system sizes. Nonetheless, an outstanding challenge is stabilizing their energy-relaxation times, which can fluctuate unpredictably in frequency and time. Here, we use qubits as spectral and temporal probes of individual two-level-system defects to provide direct evidence that they are responsible for the largest fluctuations. This research lays the foundation for stabilizing qubit performance through calibration, design, and fabrication.

Origin and higher-level diversification of acariform mites - evidence from nuclear ribosomal genes, extensive taxon sampling, and secondary structure alignment.

BACKGROUND: Acariformes is the most species-rich and morphologically diverse radiation of chelicerate arthropods, known from the oldest terrestrial ecosystems. It is also a key lineage in understanding the evolution of this group, with the most vexing question whether mites, or Acari (Parasitiformes and Acariformes) is monophyletic. Previous molecular studies recovered Acari either as monophyletic or non-monophyletic, albeit with a limited taxon sampling. Similarly, relationships between basal acariform groups (include little-known, deep-soil 'endeostigmatan' mites) and major lineages of Acariformes (Sarcoptiformes, Prostigmata) are virtually unknown. We infer phylogeny of chelicerate arthropods, using a large and representative dataset, comprising all main in- and outgroups (228 taxa). Basal diversity of Acariformes is particularly well sampled. With this dataset, we conduct a series of phylogenetically explicit tests of chelicerate and acariform relationships and present a phylogenetic framework for internal relationships of acariform mites. RESULTS: Our molecular data strongly support a diphyletic Acari, with Acariformes as the sister group to Solifugae (PP =1.0; BP = 100), the so called Poecilophysidea. Among Acariformes, some representatives of the basal group Endeostigmata (mainly deep-soil mites) were recovered as sister-groups to the remaining Acariformes (i. e., Trombidiformes + and most of Sarcoptiformes). Desmonomatan oribatid mites (soil and litter mites) were recovered as the monophyletic sister group of Astigmata (e. g., stored product mites, house dust mites, mange mites, feather and fur mites). Trombidiformes (Sphaerolichida + Prostigmata) is strongly supported (PP =1.0; BP = 98-100). Labidostommatina was inferred as the basal lineage of Prostigmata. Eleutherengona (e. g., spider mites) and Parasitengona (e. g., chiggers, fresh water mites) were recovered as monophyletic. By contrast, Eupodina (e. g., snout mites and relatives) was not. Marine mites (Halacaridae) were traditionally regarded as the sister-group to Bdelloidea (Eupodina), but our analyses show their close relationships to Parasitengona. CONCLUSIONS: Non-trivial relationships recovered by our analyses with high support (i.e., basal arrangement of endeostigmatid lineages, the position of marine mites, polyphyly of Eupodina) had been proposed by previous underappreciated morphological studies. Thus, we update currently the accepted taxonomic classification to reflect these results: the superfamily Halacaroidea Murray, 1877 is moved from the infraorder Eupodina Krantz, 1978 to Anystina van der Hammen, 1972; and the subfamily Erythracarinae Oudemans, 1936 (formerly in Anystidae Oudemans, 1902) is elevated to family rank, Erythracaridae stat. ressur., leaving Anystidae only with the nominal subfamily. Our study also shows that a clade comprising early derivative Endeostigmata (Alycidae, Nanorchestidae, Nematalycidae, and maybe Alicorhagiidae) should be treated as a taxon with the same rank as Sarcoptiformes and Trombidiformes, and the scope of the superfamily Bdelloidea should be changed. Before turning those findings into nomenclatural changes, however, we consider that our study calls for (i) finding shared apomorphies of the early derivative Endeostigmata clade and the clade including the remaining Acariformes; (ii) a well-supported hypothesis for Alicorhagiidae placement; (iii) sampling the families Proterorhagiidae, Proteonematalycidae and Grandjeanicidae not yet included in molecular analyses; (iv) undertake a denser sampling of clades traditionally placed in Eupodina, Anystina (Trombidiformes) and Palaeosomata (Sarcoptiformes), since consensus networks and Internode certainty (IC) and IC All (ICA) indices indicate high levels of conflict in these tree regions. Our study shows that regions of ambiguous alignment may provide useful phylogenetic signal when secondary structure information is used to guide the alignment procedure and provides an R implementation to the Bayesian Relative Rates test.

Dynamics of magnetization at infinite temperature in a Heisenberg spin chain.

Understanding universal aspects of quantum dynamics is an unresolved problem in statistical mechanics. In particular, the spin dynamics of the one-dimensional Heisenberg model were conjectured as to belong to the Kardar-Parisi-Zhang (KPZ) universality class based on the scaling of the infinite-temperature spin-spin correlation function. In a chain of 46 superconducting qubits, we studied the probability distribution of the magnetization transferred across the chain's center, [Formula: see text]. The first two moments of [Formula: see text] show superdiffusive behavior, a hallmark of KPZ universality. However, the third and fourth moments ruled out the KPZ conjecture and allow for evaluating other theories. Our results highlight the importance of studying higher moments in determining dynamic universality classes and provide insights into universal behavior in quantum systems.

Stable quantum-correlated many-body states through engineered dissipation.

Engineered dissipative reservoirs have the potential to steer many-body quantum systems toward correlated steady states useful for quantum simulation of high-temperature superconductivity or quantum magnetism. Using up to 49 superconducting qubits, we prepared low-energy states of the transverse-field Ising model through coupling to dissipative auxiliary qubits. In one dimension, we observed long-range quantum correlations and a ground-state fidelity of 0.86 for 18 qubits at the critical point. In two dimensions, we found mutual information that extends beyond nearest neighbors. Lastly, by coupling the system to auxiliaries emulating reservoirs with different chemical potentials, we explored transport in the quantum Heisenberg model. Our results establish engineered dissipation as a scalable alternative to unitary evolution for preparing entangled many-body states on noisy quantum processors.

Dataset of night-time emissions of the Earth in the near UV range (290-430 nm), with 6.3 km resolution in the latitude range -51.6

The data presented in this article are related to the research paper entitled "Observation of night-time emissions of the Earth in the near UV range from the International Space Station with the Mini-EUSO detector" (Remote Sensing of Environment, Volume 284, January 2023, 113336, https://doi.org/10.1016/j.rse.2022.113336). The data have been acquired with the Mini-EUSO detector, an UV telescope operating in the range 290-430 nm and located inside the International Space Station. The detector was launched in August 2019, and it has started operations from the nadir-facing UV-transparent window in the Russian Zvezda module in October 2019. The data presented here refer to 32 sessions acquired between 2019-11-19 and 2021-05-06. The instrument consists of a Fresnel-lens optical system and a focal surface composed of 36 multi-anode photomultiplier tubes, each with 64 channels, for a total of 2304 channels with single photon counting sensitivity. The telescope, with a square field-of-view of 44°, has a spatial resolution on the Earth surface of 6.3 km and saves triggered transient phenomena with a temporal resolution of 2.5 µs and 320 µs. The telescope also operates in continuous acquisition at a 40.96 ms scale. In this article, large-area night-time UV maps obtained processing the 40.96 ms data, taking averages over regions of some specific geographical areas (e.g., Europe, North America) and over the entire globe, are presented. Data are binned into 0.1° × 0.1° or 0.05° × 0.05° cells (depending on the scale of the map) over the Earth's surface. Raw data are made available in the form of tables (latitude, longitude, counts) and .kmz files (containing the .png images). These are - to the best of our knowledge - the highest sensitivity data in this wavelength range and can be of use to various disciplines.

A Review of the EUSO-Balloon Pathfinder for the JEM-EUSO Program.

EUSO-Balloon is a pathfinder for JEM-EUSO, the mission concept of a spaceborne observatory which is designed to observe Ultra-High Energy Cosmic Ray (UHECR)-induced Extensive Air Showers (EAS) by detecting their UltraViolet (UV) light tracks "from above." On August 25, 2014, EUSO-Balloon was launched from Timmins Stratospheric Balloon Base (Ontario, Canada) by the balloon division of the French Space Agency CNES. After reaching a floating altitude of 38 km, EUSO-Balloon imaged the UV light in the wavelength range ∼290-500 nm for more than 5 hours using the key technologies of JEM-EUSO. The flight allowed a good understanding of the performance of the detector to be developed, giving insights into possible improvements to be applied to future missions. A detailed measurement of the photoelectron counts in different atmospheric and ground conditions was achieved. By means of the simulation of the instrument response and by assuming atmospheric models, the absolute intensity of diffuse light was estimated. The instrument detected hundreds of laser tracks with similar characteristics to EASs shot by a helicopter flying underneath. These are the first recorded laser tracks measured from a fluorescence detector looking down on the atmosphere. The reconstruction of the direction of the laser tracks was performed. In this work, a review of the main results obtained by EUSO-Balloon is presented as well as implications for future space-based observations of UHECRs.

A checklist of bat-associated macronyssid mites (Acari: Gamasina: Macronyssidae) of Russia, with new host and geographical records.

The family Macronyssidae (Acari: Mesostigmata) comprises mostly obligate blood-sucking ectoparasites of bats (Mammalia: Chiroptera) and some other animals, such as small mammals, reptiles and birds. Here, we document and curate previously known data, and, based on our extensive survey, provide this article of bat-associated macronyssid mites of the Russian Federation. We record a total of 24 mite species belonging to 4 genera (Ichoronyssus, Macronyssus, Steatonyssus, and Cryptonyssus). Twenty-seven new host-parasite associations are reported. In addition, were provide data on five major Russian regions, for which bat-associated mite records were lacking.

Removing leakage-induced correlated errors in superconducting quantum error correction.

Quantum computing can become scalable through error correction, but logical error rates only decrease with system size when physical errors are sufficiently uncorrelated. During computation, unused high energy levels of the qubits can become excited, creating leakage states that are long-lived and mobile. Particularly for superconducting transmon qubits, this leakage opens a path to errors that are correlated in space and time. Here, we report a reset protocol that returns a qubit to the ground state from all relevant higher level states. We test its performance with the bit-flip stabilizer code, a simplified version of the surface code for quantum error correction. We investigate the accumulation and dynamics of leakage during error correction. Using this protocol, we find lower rates of logical errors and an improved scaling and stability of error suppression with increasing qubit number. This demonstration provides a key step on the path towards scalable quantum computing.

A blueprint for demonstrating quantum supremacy with superconducting qubits.

A key step toward demonstrating a quantum system that can address difficult problems in physics and chemistry will be performing a computation beyond the capabilities of any classical computer, thus achieving so-called quantum supremacy. In this study, we used nine superconducting qubits to demonstrate a promising path toward quantum supremacy. By individually tuning the qubit parameters, we were able to generate thousands of distinct Hamiltonian evolutions and probe the output probabilities. The measured probabilities obey a universal distribution, consistent with uniformly sampling the full Hilbert space. As the number of qubits increases, the system continues to explore the exponentially growing number of states. Extending these results to a system of 50 qubits has the potential to address scientific questions that are beyond the capabilities of any classical computer.

Behavior of the organs of the digestive system.

This review is concerned with interrelationships between the functions of the central organs of the digestive system. Complex interdependences determine the final result, the integral behavior of the group of organs. Thus the mechanism of the self-regulation of the function of the organ follow the natural laws for a coordinated achievement of the objective by means of the mechanism of self-regulation of the function of the group of organs. Central influences ensure correlation of the behavior of the system as a whole.

There are receptors for neurotensin in the caudate nucleus and posterior hypothalamus.

It was established in chronic experiments on dogs that the introduction of neurotensin in a dose of 3 or 10 micrograms in 1.5 microliters into the caudate nucleus changes the parameters of the conditioned and unconditioned food reflexes: a 31% shortening of the latent period and a 56% increase in the magnitude of the reflex. Microapplication of neurotensin in the same doses in the posterior region of the hypothalamus enhanced the secretory function of the gland caused by the introduction of histamine. It was concluded that the caudate nucleus and hypothalamus contain cells possessing receptors for neurotensin, which participate in mechanisms of formation of the conditioned reflex and central influence on the organs of the digestive system.

[Current clinical gastroenterology and digestive physiology (the problems of regulation)]. / Sovremennaia klinika gastroenterologii i fiziologiia pishchevareniia (problemy reguliatsii).

The paper analyzes the modern concepts of the regulation of the digestive system. The neuroendocrine control of hydrochloric acid secretion is given by the author as an example of the multifactorial and polyvariant nature of the gastrointestinal regulatory systems. The use of the experimental physiological findings in gastroenterological care is discussed.

[Concepts of K. M. Bykov and modern research on regulation of the functions of the digestive system]. / Kontseptsiia K. M. Bykova i sovremennye issledovaniia reguliatsii funktsii pishchevaritel'noi sistemy.

Use of synthetic preparations of natural peptides in studies of control of functions of the digestive system organs revealed molecular basis of central mechanisms participating in control of the stomach and pancreas secretion.

[Purinergic (P-type, nonadrenergic, noncholinergic) or peptidergic nerves?]. / Purinergicheskie (P-tip, neadrenergicheskie, necholinergicheskie) ili peptidergicheskie nervy?

Rightfulness of subdivision of the nervous system into constituting it cholinergic, adrenergic and purinergic nerves (Burnstok, 1972) is discussed in the review. A necessity of distinguishing the neurons and their fibers united under the name of peptidergic nerves, as a special type, has been stated.

[New stage in the study of the central effects on digestive system functions]. / Novyi étap v izuchenii tsentral'nykh vliianii na funktsii organov pishchevaritel'noi sistemy.

The review included author's own studies and emphasizes the problem of peptides participating in transmission of central influences to the intramural nervous system in the digestive tract's organs, to their endocrine cells or directly to the secretory (or smooth muscle) cells. The role of endocrine apparatus of the digestive tract's organs is discussed as well as the role of the so called peptidergic fibers of the vegetative nervous system in regulation of secretory function of the stomach and pancreas.

[Role of alpha-adrenoreceptors of the hypothalamus and amygdala in the response of the secretory glands of the stomach to neurotensin and somatostatin]. / Znachenie al'fa-adrenoretseptorov gipotalamusa i mindaliny v otvete sekretornykh zhelez zheludka na neirotenzin i somatostatin.

Microinjections of neurotensin and somatostatin along with alpha-adrenoblocking agent into the hypothalamus and amygdala altered the stomach secretion activated with i.v. infusion of histamine.

[Gastrin and blood proteins]. / Gastrin i belki krovi

With the aid of affinic, ion-exchange- and gel-chromatography, disc- and immunoelectrophoresis, the blood serum of healthy people and animals was shown to contain proteins capable of interaction with gastrin. These proteins form a system including, along with albumins, globulins with electrophoretic mobility of alpha- and gamma-globulins. The immunoglobulins interacting with gastrin are related to the G class. Presence of a number of forms of the labile, spatially organized structural hormonal protein complexes is suggested, which play the functional part of an effective storage and transport of the hormone from the hormone-producing cell to the effector one, and excitation of its membrane's structures. Such overmolecular complexes seem to be easier recognized by the celleffector and to exert a specific action.

[Morphologic basis for the common action of the nervous and hormonal control of gastric activity]. / Morfologicheskoe obosnovanie edinstva nervnogo i gormonal'nogo kontrolia deiatel'nosti zheludka.

In adult dogs and white Wistar rats, relationships between the automonic nerve endings, mucosal endocrine cells, mast cells, and blood capillaries in the gastric wall were studied with the aid of electron microscopy. A close association of 3 components of the regulatory mechanisms: neural, hormonal, and humoral, in the form of the triad comprising endocrine cells, autonomic nerve endings, and blood capillaries, was revealed, with no true synapses between them. Accumulations of the granules of the endocrine cells, synaptic vesicles of the autonomic nerves, and the pinocytose vesicles of the capillary endothelium were seen at inner surface of the cells' membranes which is the morphological indication of the physiological function. The data obtained suggest that the interaction between the 3 above components is realised through the diffuse synapses, and indicate that the interstitium of the digestive tract wall is the area of integration of the neural and the hormonal links of neuro-homoral visceral reflexes.