The ability to engineer parallel, programmable operations between desired qubits within a quantum processor is key for building scalable quantum information systems
. In most state-of-the-art ...approaches, qubits interact locally, constrained by the connectivity associated with their fixed spatial layout. Here we demonstrate a quantum processor with dynamic, non-local connectivity, in which entangled qubits are coherently transported in a highly parallel manner across two spatial dimensions, between layers of single- and two-qubit operations. Our approach makes use of neutral atom arrays trapped and transported by optical tweezers; hyperfine states are used for robust quantum information storage, and excitation into Rydberg states is used for entanglement generation
. We use this architecture to realize programmable generation of entangled graph states, such as cluster states and a seven-qubit Steane code state
. Furthermore, we shuttle entangled ancilla arrays to realize a surface code state with thirteen data and six ancillary qubits
and a toric code state on a torus with sixteen data and eight ancillary qubits
. Finally, we use this architecture to realize a hybrid analogue-digital evolution
and use it for measuring entanglement entropy in quantum simulations
, experimentally observing non-monotonic entanglement dynamics associated with quantum many-body scars
. Realizing a long-standing goal, these results provide a route towards scalable quantum processing and enable applications ranging from simulation to metrology.
Understanding topological matter is an outstanding challenge across several disciplines of physical science. Programmable quantum simulators have emerged as a powerful approach to studying such ...systems. While quantum spin liquids of paradigmatic toric code type have recently been realized in the laboratory, controlled exploration of topological phases with non-Abelian excitations remains an open problem. We introduce and analyze a new approach to simulating topological matter based on periodic driving. Specifically, we describe a model for a so-called Floquet spin liquid, obtained through a periodic sequence of parallel quantum gate operations that effectively simulates the Hamiltonian of the non-Abelian spin liquid in Kitaev’s honeycomb model. We show that this approach, including the toolbox for preparation, control, and readout of topological states, can be efficiently implemented in state-of-the-art experimental platforms. One specific implementation scheme is based on Rydberg atom arrays and utilizes recently demonstrated coherent qubit transport combined with controlled-phase gate operations. We describe methods for probing the non-Abelian excitations, and the associated Majorana zero modes, and simulate possible fusion and braiding experiments. Our analysis demonstrates the potential of programmable quantum simulators for exploring topological phases of matter. Extensions including simulation of Kitaev materials and lattice gauge theories are also discussed.
Rhodococcus equi (R. hoagii) is an opportunistic pathogen commonly found in foals up to 6 months old and animal environment. The R. equi genome contains genetically stable chromosomal DNA and an ...80-90 kb plasmid containing vapA gene, responsible for virulence. Most reports from around the world focus on the determination of R. equi plasmid profiles. Few studies have attempted to determine differences in nucleotide sequences between virulent strains of R. equi isolated from foals and breeding environment. The aim of the study was to perform a molecular analysis of a fragment of the chromosomal gene encoding the 16S rRNA subunit and the vapA plasmid gene of virulent R. equi strains isolated on Polish studs from foals and from the breeding environment of horses. The sequencing method was used to compare the primary structure of fragments of the chromosomal and plasmid DNA of the virulent R. equi strains. The sequences of 22 clinical and 18 environmental R. equi isolates were compared with the sequences of the gene fragments of reference strains available in the NCBI GenBank database. All sequenced 16S rRNA amplicons of Polish field strains were identical and showed 99.5% similarity to the four randomly selected sequences of this gene fragment in the GenBank database. The results confirm that fragments of the 16S rRNA gene of R. equi strains are highly conserved and do not undergo variation in field conditions. Analysis of the sequencing results for the vapA gene fragment of the strains used in our study revealed two polymorphic variants and clear differences between the sequences of strains isolated from foals and from soil samples. Presumably, R. equi strains present in the breeding environment are more exposed than clinical strains to adverse external factors. This may result in changes in the DNA sequence due to natural selection.
The transport of refrigerated cargo (fruit and vegetable) imported from Spain toPoland is realized mainly by road. At the moment, there are no specialized short-seashipping services of citrus fruit ...from Spain. In the previous years, only an insignificantamounts of fruit was transported from Spain to the Polish seaports.The aim of this article is to identify and characterize supply chains and logisticstransportinfrastructure used in the freight of refrigerated cargo between Poland andSpain. The particular emphasis is put on the characteristics of supply chains of citrus fruitand vegetables.
Financial markets can play a role in sustaiability development. They can support sustainability by making ESG disclosure, launching sustainability related indices or offering sustainability guidance ...for listing companies. All of these activities helps in developing sustainability. This article is an attempt to analyze sustainability support level in stock exchanges in the world. It is based on a survey conducted in 27 stock exchanges. The aim of this article is to assess the level of stock exchanges sustainability support and examine the relationship between the stock market size and sustainability support level. To acheve the aim the assessment tool has been created. Sustainability Support Index is a synthetic stock markets sustainability support measure. It helps to compare stock exchange sustainability support levels. In the article statistical tools are used to compare the phenomena, mainly regression analysis and Pearson's correlation. The conclusion presented in the article states that there is a differential stock market sustainability support level in the world. There is no clear correlation between sustainability support variables and stock market size variables.
Demonstrating quantum advantage requires experimental implementation of a computational task that is hard to achieve using state-of-the-art classical systems. One approach is to perform sampling from ...a probability distribution associated with a certain class of highly entangled many-body wave functions. It has been suggested that such a quantum advantage can be certified with the linear cross-entropy benchmark (XEB). We critically examine this notion. First, we consider a “benign” setting, where an honest implementation of a noisy quantum circuit is assumed, and characterize the conditions under which the XEB approximates the fidelity of quantum dynamics. Second, we assume an “adversarial” setting, where all possible classical algorithms are considered for comparisons, and show that achieving relatively high XEB values does not imply faithful simulation of quantum dynamics. Specifically, we present an efficient classical algorithm that achieves high XEB values, namely 5–12% of those obtained in the state-of-the-art experiments, within just a few seconds using a single GPU machine. This is made possible by identifying and exploiting several vulnerabilities of the XEB, which allows us to achieve high XEB values without simulating a full quantum circuit. Remarkably, our algorithm features better scaling with the system size than a noisy quantum device for commonly studied random circuit ensembles in various architecture. We quantitatively explain the success of our algorithm and the limitations of the XEB by using a theoretical framework, in which the dynamics of the average XEB and fidelity are mapped to classical statistical mechanics models. Using this framework, we illustrate the relation between the XEB and the fidelity for quantum circuits in various architectures, with different choices of gate sets, and in the presence of noise. Taken together, our results demonstrate that XEB’s utility as a proxy for fidelity hinges on several conditions, which should be independently checked in the benign setting, but cannot be assumed in the general adversarial setting. Therefore, the XEB on its own has a limited utility as a benchmark for quantum advantage. We briefly discuss potential ways to overcome these limitations.
COMPETITION IN POLITICS Kalinowski, Marcin
Ekonomia i Prawo,
09/2014, Letnik:
13, Številka:
3
Journal Article
Recenzirano
Odprti dostop
The article illustrates the competition in politics which takes place in two parallel dimensions, i.e. during regular electoral campaigns and during the period of debating the final version of the ...legislation. One of the ways to the appropriate treatment of competition in politics is focusing research efforts on the analysis of political entrepreneurs behavior. It involves obtaining an advantage over players aiming to achieve identical objectives through the use of various instruments which exert influence on the preferences of political consumers as well as public decision of politicians and bureaucrats. The author argues that these behaviors are an adjustment to the conditions in which competition takes place on the political market. The methodology adopted in the study based on the hypothesis that individuals make public choices thus affecting the final outcome of the political process, and a direct relationship between the private cost and private benefit, which is a fundamental feature of the market selection, can be transferred to the analysis of public sphere.
Canine babesiosis is a disease caused by infection with parasites of the genus
. These protozoa are classified as either large (e.g.,
) or small (e.g.,
). So far, only three small
species of clinical ...importance, able to infect dogs, have been described:
,
, and
. This review presents the current epidemiological situation of
infections in dogs in Europe. In most European countries where
has been reported, the percentage of infected dogs is around 1%. The higher prevalence of the
infection among American Pit Bull Terriers suggests breed susceptibility. An analysis of the available data makes it possible to conclude that
infections may appear in the future in other non-endemic regions of Europe, which may pose significant diagnostic and therapeutic challenges for veterinary practitioners.
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